Speed reducer special for mechanical arm

The utility model discloses a speed reducer special for a mechanical arm. Including a housing, a cavity is formed in the shell; an output shaft is movably connected to the position, close to the top,of one side of the shell through a rotating shaft, one end of the output shaft penetrates through the shell and extends into the shell, an input shaft is movably connected to the position, close to the top, of the other side of the shell through a rotating shaft, and one end of the input shaft penetrates through the shell and is fixedly connected with the output shaft. Speed reducer special for mechanical arm, the mechanical arm and the input shaft are integrally designed; the distance between the manipulator and the shell is shortened; the device is more compact in structure, a user can conveniently use the device in a narrow space, the working platform and the shell are connected together through cooperative use of the fixing plates, the supporting beams, the locking plates, the clampinggrooves, the clamping blo