Power transmission device

A power transmission device comprising:

• an input shaft rotatable about a first rotation axis;
• first wire and second wire configured to be wound around an outer surface of the input shaft based on a first radial direction, each of the first and second wires having a first side fixed to the input shaft, the first wire and the second wire being separate;
• an output shaft rotatable about a second rotation axis, the output shaft comprising:
• a shaft body , wherein the first and second wires surround an outer surface of the shaft body based on a second radial direction;
• a first protrusion region provided on the outer surface of the shaft body based on the second radial direction and protruding in the second radial direction of the shaft body;
• a second protrusion region provided on the outer surface of the shaft body based on the second radial direction and protruding in the second radial direction of the shaft body;
• and
• first and second wire holders to which a second side of the first wire and a second side of the second wire are respectively fixed;
• a base member provided at one side of the output shaft, wherein the output shaft is rotatably coupled to the base member;
• and
• a third protrusion region disposed at one side of the base member;
• wherein the first wire extends from the first side of the first wire to the second side of the first wire so that the first wire extends from the input shaft toward the third protrusion region, the first wire is bent while surrounding the third protrusion region, and the first wire extends in a first circumferential direction of the shaft body;
• and
• wherein the second wire extends from the first side of the second wire to the second side of the second wire so that the second wire extends in a second circumferential direction opposite to the first circumferential direction of the shaft body, the second wire is bent while surrounding the second protrusion region, and then the second wire extends in the first circumferential direction of the shaft body.

A power transmission device comprising:

• an input shaft rotatable about a first rotation axis;
• first wire and second wire configured to be wound around an outer surface of the input shaft based on a first radial direction, each of the first and second wires having a first side fixed to the input shaft, the first wire and the second wire being separate;
• an output shaft rotatable about a second rotation axis, the output shaft comprising:
• a shaft body, wherein the first and second wires surround an outer surface of the shaft body based on a second radial direction;
• a first protrusion region provided on the outer surface of the shaft body based on the second radial direction and protruding in the second radial direction of the shaft body;
• a second protrusion region provided on the outer surface of the shaft body based on the second radial direction and protruding in the second radial direction of the shaft body;
• and
• first and second wire holders to which a second side of the first wire and a second side of the second wire are respectively fixed;
• a base member provided at one side of the output shaft, wherein the output shaft is rotatably coupled to the base member;
• a third protrusion region disposed at one side of the base member;
• an idler member facing the base member with the output shaft interposed therebetween, the idler member being coupled to the output shaft and rotatable relative to the output shaft;
• wherein the first wire extends from the first side of the first wire to the second side of the first wire so that the first wire extends in a first circumferential direction in a state of being in close contact with an outer surface of the idler member based on the second radial direction, the first wire is bent while surrounding the first protrusion region, and then the first wire extends in a second circumferential direction opposite to the first circumferential direction of the shaft body in a state of being in close contact with the outer surface of the shaft body based on the second radial direction;
• and
• wherein the second wire extends from the first side of the second wire to the second side of the second wire so that the second wire extends in the second circumferential direction of the shaft body, the second wire is bent while surrounding the second protrusion region, and then the second wire extends in the first circumferential direction of the shaft body.