Internal linkage structure of main shaft pull rod

The invention relates to a main shaft, in particular to an internal linkage structure of a main shaft pull rod. The main shaft comprises a shaft core, a pull rod and a piston moving axially, the pull rod penetrates through the shaft core, a fixing pin penetrates through the pull rod in the radial direction and is fixedly connected with the pull rod, the shaft core is sleeved with a sliding sleeve, the two ends of the fixing pin penetrate through the shaft core and penetrate into the sliding sleeve, and the two ends of the fixing pin are fixedly connected with the sliding sleeve. The piston is provided with an axial face facing the end face of the sliding sleeve and used for pushing the sliding sleeve, the fixing pin and the pull rod to move axially through the axial face. The fixing pin penetrates through the pull rod, the two ends of the fixing pin are fixedly connected with the sliding sleeve, the piston pushes the pull rod through the sliding sleeve and the fixing pin, the surface of the fixing pin is not