Flexible spring and transmission assembly

The utility model discloses a flexible spring and a transmission assembly, the flexible spring comprises an axis, a spring body composed of a first connecting part with first rigidity and an annular body with second rigidity, a second connecting part and a mounting part arranged in a cavity, a first hole penetrating through the mounting part in the axis direction is formed in the mounting part, the annular body surrounds in the circumferential direction of the axis to form a closed-loop cavity, the axis penetrates through the center point of the cavity, and the first connecting part is provided with a first end operatively connected with the inner circumferential face of the annular body and a second end operatively connected with the outer circumferential face of the mounting part; the first connecting part extends in the radial direction of the axis, the second connecting part comprises a first section and a second section, the first section and the annular body are integrally arranged in a penetrating mode