A transmission is able to convert a rotating motion into a translating motion by means of a rotational driving device and a transmissional component which is able to translate along a guiding part. The said transmission is connected with the driving device mechanically. It is simple in structure, light in weight and the friction force is small when it is subjected to tension and oppression. The transmissional component may be at least divided into two parts along the axial direction of the guiding part. In the guiding part, they are meshed each other with teeth and outside the guiding part, the transmissional part may be divided at the vertical direction of the guiding part, deforms and links with the driving device with a coupling. |