Arm structure of robot and robot

An arm structure of a robot, the arm structure comprising:

• a proximal arm member;
• a first motor attached to the proximal arm member;
• a second motor attached to the proximal arm member;
• a first bearing attached to a distal end of the proximal arm member, the first bearing having a center axis substantially parallel to an axis of an output shaft of the first motor;
• a distal arm member supported on the distal end of the proximal arm member by the first bearing;
• a first gear positioned coaxially with the first bearing and configured to rotate together with the first bearing;
• a first motor transmission gear attached to the proximal arm member, the first motor transmission gear transmitting rotation force of the first motor to the first gear to make the distal arm member swing about the center axis of the first bearing;
• a second bearing attached to the distal arm member, the second bearing having a center axis perpendicular to the center axis of the first bearing;
• a rotary member supported on the distal arm member by the second bearing, the rotary member being rotatable relative to the distal arm member;
• a second gear attached to the rotary member and positioned coaxially with the second bearing;
• and
• a second motor transmission gear attached to the proximal arm member or the proximal arm member and the distal arm member, the second motor transmission gear transmitting rotation force of the second motor to the second gear to make the rotary member rotate about the center axis of the second bearing.