To provide a reduction gear configured to suppress or eliminate backlash.
A reduction gear includes: a ring gear 6 with a plurality of gear teeth 6a formed on the inner circumference thereof; a first revolving gear 7 with gear teeth 7a meshed with the gear teeth 6a; a first eccentric cam 11 provided in a center position of the first revolving gear 7 so as to be rotated with respect to the first revolving gear 7; a center shaft 5 around which the first eccentric cam 11 turns and around which the first revolving gear 7 revolves; a penetrating pin 13 which is inserted into a first through hole 7c formed in the first revolving gear 7; and a second support plate 17 which includes a second connecting hole 17a which is connected by inserting the penetrating pin 13 therein, supports the penetrating pin 13, and outputs turning generated by the rotation of the first revolving gear 7. The first revolving gear 7 includes a first receiving portion 14 having elasticity between the first through hole 7c and the penetrating pin 13, and the second support plate 17 includes a fourth receiving portion 23 having elasticity between the second connecting hole 17a and the penetrating pin 13.
Osamu Suzawa
Kazuhiko Miyasaka