Structure of joint of robot including drive motor and reduction gear

A structure of a joint of a robot in which a first member and a second member are jointed through intermediation of a joint and in which the first member and the second member turn relatively to each other, the structure of the joint comprising:

• a drive motor configured to drive the second member with respect to the first member;
• a reduction gear including an input shaft configured to receive rotational force of the drive motor, a gear configured to transmit rotational force of the input shaft, a gear support member configured to support the gear, and a reduction gear case to which rotational force of the gear is transmitted;
• and
• an interposition member interposed between the drive motor and the first member, wherein
• the drive motor is fixed to the interposition member with a plurality of motor fixing bolts arranged in a circumferential direction,
• the interposition member is fixed to the first member,
• the gear support member is fixed to the first member with a plurality of support member fixing bolts arranged in the circumferential direction,
• the reduction gear case is fixed to the second member,
• the motor fixing bolts and the support member fixing bolts are arranged at positions such that a diameter of the positions where the motor fixing bolts are arranged and a diameter of the positions where the support member fixing bolts are arranged are smaller than an outer diameter of the reduction gear case, and
• the interposition member has a shape for fixing the motor fixing bolts at positions away from the support member fixing bolts.