Adjustable straw multi-stage crushing and scattering returning machine

The invention relates to an adjustable straw multi-stage crushing and scattering returning machine, and belongs to the technical field of agricultural machinery. The transmission system assembly, the main smashing knife roll assembly, the smashing device sliding rail assembly, the uniform scattering device assembly and the walking device assembly are installed on the machine frame assembly, and the uniform scattering device assembly is installed on the rear side of the machine frame assembly to complete uniform scattering of smashed straw. The main crushing knife roll assembly and the third-stage saw disc knife assembly are respectively in transmission connection with the transmission system assembly, and the first-stage stationary knife assembly, the second-stage stationary knife assembly and the third-stage saw disc knife assembly are mounted on the crushing device sliding rail assembly in a matched manner. And the circumferential and radial relative positions of the main crushing knife roll assembly, the f