Robot arm driving unit

A driving unit that rotates a first member and a second member constituting a robot arm about a rotary axis, the driving unit comprising:

• a bracket fixed to the first member and including a first hollow hole penetrating along the rotary axis;
• a motor fixed to the bracket and accommodated in the first member;
• a reducer configured to connect the bracket and the second member such that the bracket and the second member are rotatable about the rotary axis, wherein a second hollow hole penetrates through the reducer along the rotary axis;
• a wire penetrating through the first hollow hole and the second hollow hole and routed from an inside of the first member to an inside of the second member;
• a first fixation member that fixes the wire to the bracket or the motor in the first member;
• a second fixation member that fixes the wire to the reducer in the second member;
• and
• a driving power transmission mechanism accommodated in the bracket and transmitting a rotation of the motor to the reducer, wherein the driving power transmission mechanism includes a driving shaft, a first transmission mechanism that transmits the rotation of the motor to the driving shaft, and a second transmission mechanism that transmits a rotation of the driving shaft to an input shaft of the reducer, and a distance between a shaft of the motor and the rotary axis is shorter than a distance between the driving shaft and the rotary axis.