Transmission unit of motor vehicle adjusting and driving device

The utility model relates to a transmission unit (1) of a motor vehicle adjusting and driving device, particularly a car window lifting and driving device. The transmission unit comprises a transmission device shell (2,2a) and a shaft bolt (4) which is rotationally connected with the transmission device shell and is used for rotatably supporting a transmission wheel (3), particularly a worm drive device, wherein the shaft bolt (4) comprises a first shaft section (4a) with a first outer diameter (d1) and a second shaft section (4b) which is connected with the first shaft section (4a) and comprises a free end section (4c) on the end side; and the outer diameter (d2) of the second shaft section on at least one part of the section length in the axial direction is smaller than the outer diameter (d1) of the first shaft section (4a). The utility model relates to a shaft bolt which is particularly used for the transmission unit (1).