ROCKING DIFFERENCE REDUCTION GEAR

PROBLEM TO BE SOLVED: To obtain a high reduction ratio with a small-sized and simple structure.SOLUTION: A rocking gear body 8 is rotatable in relation to a rocking shaft portion 3c around an axis C2. An outer circumferential part of the rocking gear body 8 is formed with an input side outer gear 9 meshed with an input side inner gear 2, and an output side outer gear 10 meshed with an output side inner gear 6. The input side outer gear 9 is meshed with the input side inner gear 2 by the rotation of a crankshaft 3 around an input shaft portion 3a, and the inside of the input side inner gear 2 is made to rock (revolve). The output side outer gear 10 is integrally rotated with the input side outer gear 9, meshed with the output side inner gear 6, and the inside of the output side inner gear 6 is made to rock (revolve). The difference between the number of the teeth of the input side inner gear 2 and the number of the teeth of the output side inner gear 6 is equal to the difference between the number of the teeth of the input side outer gear 9 and the number of the teeth of the output side outer gear 10.