Patent ID: 8646360

Claim:
A flexspline that is a structural component of a wave gear device, the flexspline of the wave gear device comprising: a radially flexible cylindrical body extending in an axial direction; a disc-shaped diaphragm continuous with one open end of the cylindrical body, the disc-shaped diaphragm extending outward in a radial direction that is substantially perpendicular to the axial direction, wherein the diaphragm has a first length in the radial direction; a rigid, annular flange continuous with an outer peripheral edge of the diaphragm; and external teeth formed on an outer peripheral surface portion of the cylindrical body on another open end thereof; wherein the annular flange has a first annular part extending in the axial direction from the outer peripheral edge of the diaphragm in a direction away from the cylindrical body, and a second annular part at a leading end of the first annular part which protrudes inwardly in a radial direction and having a second length in the radial direction, wherein the second annular part has a uniform thickness as measured in the axial direction, and the uniform thickness of the second annular part is greater than a thickness of the disc-shaped diaphragm as measured in the axial direction; wherein the first length of the diaphragm in the radial direction is greater than the second length of the second annular part in the radial direction; and the second annular part is parallel to and separate from the disc-shaped diaphragm so as to form a gap between the second annular part and the disc-shaped diaphragm.