Stepless transmission

A stepless transmission comprises two transmission wheels and a conveying belt used for transmission connection of the two transmission wheels, wherein the two transmission wheels serve as a driving wheel and a driven wheel correspondingly; each transmission wheel comprises a shell with a closed inner cavity and fluid filled in the inner cavity; and each shell can change the diameter of the corresponding transmission wheel by means of stretching or compressing in the axial direction. The stepless transmission is simple in structure and low in manufacturing cost. 种无级变速器，包括分别作为主动轮、从动轮的两个传动轮，以及用于将两个所述传动轮传动连接的传动带；所述传动轮包括具有封闭内腔的外壳以及填充于所述内腔中的流体，所述外壳可通过沿轴向的拉伸或压缩来改变所述传动轮的直径。本发明的无级变速器结构简单、制造成本低。