Robot arm

A robot arm comprising:

• a shoulder joint assembly which is connected to an upper arm portion, and includes a drive unit for generating driving power;
• an elbow joint assembly which is provided between the upper arm portion and a forearm portion, and operates by being supplied with driving power from the drive unit;
• and
• a wrist joint assembly which is provided between the forearm portion and a hand portion, and operates by being supplied with driving power from the drive unit,
• wherein the elbow joint assembly includes,
• a stationary member which is connected to the upper arm portion, and has a first curved surface portion formed as at least a part of a circumference of the stationary member is formed in an arc shape,
• a rotating member which is connected to the forearm portion, has a second curved surface portion formed as at least a part of a circumference of the rotating member is formed in an arc shape being in contact with the first curved surface portion, and is rotated along the first curved surface portion,
• at least a pair of first pulleys which is eccentrically provided at one side of the stationary member and one side of the rotating member based on a rotation center point with respect to the first curved surface portion and the second curved surface portion,
• at least a pair of second pulleys which is eccentrically provided at the other side of the stationary member and the other side of the rotating member based on the rotation center point with respect to the first curved surface portion and the second curved surface portion,
• a first wire part which is wound around the pair of first pulleys, and has one side extending toward the drive unit,
• a second wire part which is wound around the pair of second pulleys, and has one side extending toward the drive unit,
• a first connecting pulley and a second connecting pulley provided on a first portion of the stationary member and the rotating member, respectively,
• a third connecting pulley and fourth connecting pulley provided on a second portion which is different from the first portion of the stationary member and the rotating member, respectively,
• a third wire part which is wound around the first connecting pulley and the third connecting pulley, and
• a fourth wire part which is wound around the second connecting pulley and the fourth connecting pulley.