Patent ID: 8827052

Claim:
A decelerator comprising: a first deceleration unit, wherein the first deceleration unit includes: a sun gear configured to rotate coaxially with an input shaft; a plurality of planet gears distributed around the sun gear so as to rotate on its axis during rotation of the sun gear; and a ring gear configured to circumscribe the plurality of planet gears so as to eccentrically rotate during rotation of the planet gears; and a second deceleration unit, wherein the second deceleration unit includes: an inner gear formed on an outer circumference thereof with cycloid teeth so as to eccentrically rotate along with the ring gear located inside an inner circumference thereof and which has a plurality of through-holes circumferentially distributed between the inner circumference and the outer circumference thereof; an outer gear located around the inner gear and which has teeth formed on an inner circumference thereof to correspond to the cycloid teeth; and an output member which is provided around the center of one surface thereof with a plurality of circumferentially distributed bosses having a smaller diameter than the through-holes so as to be inserted into the through-holes and which is provided at the center of the other surface thereof with an output shaft; wherein a bearing is integrally fixed around the ring gear.