BACKGROUND

Technical Field

Certain embodiments of the present invention relate to an eccentric oscillation type speed reducer.

Description of Related Art

In the related art, the applicant of this application disclosed a planetary speed reducing mechanism provided with an external gear which is oscillated by an eccentric body, and an internal gear with which the external gear internally meshes.

SUMMARY

According to an embodiment of the present invention, an eccentric oscillation type speed reducer includes: an external gear which meshes with the internal gear; an eccentric body shaft which oscillates the external gear; and an input shaft bearing which supports the eccentric body shaft. The casing and the external gear are made of resin, and the input shaft bearing is made of metal.

The casing and the external gear may be made of resin, and the input shaft bearing may be made of metal. The eccentric body shaft may be made of metal. The eccentric oscillation type speed reducer may include a carrier disposed at a side portion of the external gear in an axial direction, the carrier is made of metal.

According to another embodiment of the present invention, there is provided an eccentric oscillation type speed reducer including: an internal gear provided in a casing; an external gear which meshes with the internal gear; a carrier disposed at a side portion of the external gear in an axial direction; and a main bearing disposed between the carrier and the casing. The casing and the external gear are made of resin, and the main bearing is made of metal. The carrier may be made of metal.

