Speed change gear and manufacturing method therefor

A speed change gear comprising:

• an internal gear member that supports an input shaft and an output shaft rotatably about a common input/output axis, and that has an internal gear on its inner peripheral surface;
• an eccentric member that centers on an eccentric axis that is eccentric with respect to the input/output axis;
• an annular oscillating member that is rotatably supported on an outer peripheral side of the eccentric member, that has an external gear that is formed on its outer peripheral surface so as to be able to be in mesh with the internal gear and a through-hole having a cylindrical inner surface that centers on a position radially spaced apart from the input/output axis, and that oscillatingly rotates around the input/output axis;
• a pair of first and second rotating members that are arranged so as to face in a direction along the input/output axis across the oscillating member, that are supported by the internal gear member rotatably about the input/output axis, and each of which has an insertion hole that has a cylindrical inner surface and is smaller in diameter than the through-hole;
• and
• a columnar pin that is supported at both ends in such a manner that the pin extends through the through-hole, and one side end portion of the pin is inserted in one of the insertion holes of the first rotating member and second rotating member and the other side end portion of the pin is inserted in the other one of the insertion holes of the first rotating member and second rotating member, wherein
• the insertion hole of the first rotating member and the insertion hole of the second rotating member have the same diameter, and
• an outside diameter of the other side end portion of the pin is smaller than an outside diameter of the one side end portion of the pin such that the one side end portion is press-fitted in the corresponding insertion hole with interference and the other side end portion is inserted in the corresponding insertion hole in a contact state or with a gap under no pressure.