Flexspline and wave gear

Abstract

Flexspline (100), comprising: a cylindrical section (110) comprising an inner surface surrounding an opening (130), and a flanged section (120) connected to an end of the cylindrical section (110) and extended radially outwards, wherein a portion of the flanged section (120) near the cylindrical section (110) is recessed to form a bottom wall (122) and an inner wall (121), the bottom wall (122) being connected to the cylindrical section (110) and parallel to the radial direction, and the inner wall (121) being connected to the bottom wall (122) and parallel to an axial direction (X1), wherein a bottom surface of the bottom wall (122) comprising a first arc region (122a) and a second arc region (122b) being connected to each other, and the bottom surface facing the cylindrical section (110),a first radius of curvature of the first arc region (122a) differs from a second radius of curvature of the second arc region (122b) and contains a connecting line (L1) between the first arc region (122a) and the second arc region (122b), wherein a first distance D1 between the inner wall (121) and the inner surface along the radial direction and a second distance D2 between the inner wall (121) and the connecting line (L1) along the radial direction satisfy a condition 5.75 ≤ D1 / D2 ≤ 6.10.