Patent ID: 8714045

Claim:
A robot joint driving apparatus comprising: a reversible drive motor; a motor gear disposed on an end portion of the reversible drive motor, rotated according to an operation of the drive motor; a ball nut part rotated according to an operation of the drive motor; a gear part, directly connected to the ball nut part and directly engaged with the motor gear through physical contact with the motor gear; a ball screw part performing linear movement according to the rotation of the ball nut part; a wire connected to the ball screw part at first and second sides of the ball screw part; an idle pulley rotatably installed at a first side of the wire; and a joint part rotatably installed at a second side of the wire opposite the first side, wherein the ball nut part includes a first ball nut part screwed to the gear part and a second ball nut part screwed to the first ball nut part, wherein the second ball nut part includes a cylindrical body protruding from an inner surface of the second ball nut part, which is inserted into a hollow portion of the first ball nut part.