SPEED REDUCER

摘要

The invention is related to a speed reducer comprising: a first planetary gear group having first, second, and third planetary gears within a small diameter part formed integrally with a large diameter part; a first ring gear which is engaged with the small diameter part of the planetary gears; a second planetary gear group having fourth , fifth , and sixth planetary gears which are secured on a second distribution plate about a hinge shaft at a degree of 1 20° and of which the small diameter part is engaged with the outward gear of the first ring gear; a second ring gear inserted into the first ring gear to be engaged with the large diameter of the first, second, and third planetary gears; and an output part engaged with the large diameter part of the fourth , fifth , and sixth planetary gears.