Robot and robot system

A robot system comprising:

• a robot;
• and
• a control device that controls driving of the robot, wherein
• the robot includes
• a base,
• a first arm that is joined to the base and that rotates around a first rotation axis with respect to the base,
• a second arm that is joined to the first arm and that rotates around a second rotation axis, which is parallel to the first rotation axis, with respect to the first arm,
• a work head that includes a spline shaft which is disposed at the second arm and which is disposed along a third rotation axis parallel to the first rotation axis and a spline nut which is mounted on the spline shaft, and in which the spline shaft rotates around the third rotation axis when the spline nut is rotated, and
• a spline shaft first drive mechanism that rotates the spline nut to rotate the spline shaft around the third rotation axis,
• the spline shaft first drive mechanism includes a motor and a power transmission mechanism that transmits rotation of the motor to the spline nut,
• the power transmission mechanism has a first pulley that is fixed to a rotation shaft of the motor, a second pulley that is fixed to the spline nut, an intermediate pulley that is supported by a support member via a bearing and that rotates around a fourth rotation axis, which is parallel to the first rotation axis, with respect to the second arm, a first belt that is wound around the first pulley and the intermediate pulley, and a second belt that is wound around the intermediate pulley and the second pulley,
• the intermediate pulley has a first intermediate pulley around which the first belt is wound, a second intermediate pulley that is disposed side by side with the first intermediate pulley in a direction along the fourth rotation axis and around which the second belt is wound, and a shaft portion that is disposed along the fourth rotation axis and that couples the first intermediate pulley and the second intermediate pulley,
• the bearing is disposed between the first intermediate pulley and the second intermediate pulley,
• one of the first intermediate pulley and the second intermediate pulley has a recess portion that is open to another side, and
• at least a part of the bearing is positioned in the recess portion.