Parallel shaft speed reducer adjustable in center distance

The invention relates to a parallel shaft speed reducer, in particular to a parallel shaft speed reducer adjustable in center distance. The parallel shaft speed reducer is composed of a speed reducer shell, an input shaft, an output shaft A, an output shaft B, a mandrel A and a mandrel B, the input shaft is mounted at one end in the speed reducer shell, slide rails are mounted at the other end in the speed reducer shell, a baseplate is mounted on the slide rails, the output shaft A is mounted on the upper surface of the baseplate, the output shaft B is mounted between the input shaft and the output shaft A, a connecting rod A is mounted on the output shaft A, a connecting rod B is mounted on the output shaft B, the mandrel A is fixedly mounted on the connecting rod B, and the connecting rod A and the connecting rod B are connected through the mandrel B. Adjusting of various center distances can be realized through the connecting rod A and the connecting rod B, so that the problems that existing speed reducers with standard center distances are often limited by space and cannot be used and custom-making of speed reducers with nonstandard center distances is high in price are solved, and application range is expanded. The parallel shaft speed reducer adjustable in center distance has the advantages of simple structure, high efficiency, stability in operating, small impact and large impact load.