Triple harmonic speed reducer

A triple harmonic speed reducer, comprising:

• a wave generator;
• a flexspline and a rigid circular spline;
• wherein the flexspline includes a flexible inner gear and an output part, the wave generator is arranged in an inner installation cavity of the flexible inner gear, the wave generator includes an input shaft end and a cam, wherein a flexible bearing is annularly arranged between an outer ring peripheral surface of the cam and an inner ring peripheral surface of the flexible inner gear, the cam of the wave generator is of a three-convex structure, three convex ring surfaces are annularly arranged on the outer ring periphery of the cam uniformly, a gradual transition ring surface is provided between every two adjacent convex ring surfaces, a tooth part of the flexible inner gear is meshed with a corresponding outer gear of the rigid circular spline, and the rigid circular spline is fixedly connected to an outer casing by a peripheral connecting flange;
• wherein all the convex ring surfaces of the cam are of the same structure, and all the gradual transition ring surfaces of the cam are of the same structure;
• and
• wherein the convex ring surface comprises a central most convex point and transition arcs on both sides and the gradual transition ring surface comprises a central most concave region and gradual transition arcs on both sides, wherein the end of the transition arc on a corresponding side of the convex ring surface is connected with an end of the gradual transition arc on a corresponding side of the gradual transition ring surface.