Planetary type speed reducer having compound planets and method of constructing such planets

摘要

A planetary type speed reducer provides a large central hole for passing electric and service lines for a robot therethrough. The speed reducer may be used in either a self-motorized or an externally-motorized rotary joint. In a predetermined embodiment, the speed reducer includes a cylindrical carrier and multiple compound gear planets which are rotatably mounted on their respective shafts some of which, in turn, are eccentrically mounted on the carrier. A method for manufacturing the gear planets is also provided. Each of the gears has two sections or parts which are shifted angularly relative to each other and are adapted to engage adjacent fixed output gears of the rotary joint.