Patent ID: 8651997

Claim:
A planetary gear reducer comprising: a planetary gear having a revolution center located inside the planetary gear and provided with a plurality of engaging holes passing therethrough in an axial direction; a carrier; and a plurality of pins secured to the carrier and passing through the engaging holes for operating the carrier together with rotation movement of the planetary gear through engagements with the engaging holes; wherein: the carrier comprises a first side plate that is formed to a disc plate shape and that fixes the pins thereto to protrude the pins from one end surface in the axial direction; the outside diameter of the first side plate is formed to be a small diameter on one side in the axial direction and a large diameter on the other side in the axial direction; and the first side plate is provided with: press-fitting hole portions with the pins press-fitted thereinto; small-diameter side concavities that are formed at the press-fitting hole portions on the one side in the axial direction, that open to the one end surface in the axial direction of the first side plate and that have internal surfaces being out of contact with the pins at at least parts thereof, and the plurality of pins each have a press-fitting shaft portion that has a constant outside diameter in an axial direction, the press-fitting shaft portions being press fitted into the press-fitting hole portions and passing through the engaging holes.