Hollow hydraulic spinner

The invention discloses a hollow hydraulic spinner which comprises a shell. An oil cylinder body, a piston rod and a fork head are mounted in the shell. A piston is mounted at the position, in the cylinder body, of the piston rod. A pipeline is arranged in the cylinder body. One end of the pipeline is connected with an oil inlet and an oil outlet in the two ends of the piston, and the other end of the pipeline communicates with a rotary joint mounted on the cylinder body. A pawl is mounted on the fork head and provided with a floating claw and a floating claw pressure spring. A pawl tension spring is mounted on the pawl. A transmission ratchet wheel and drive shaft assembly, a backstop claw and a backstop claw tension spring are mounted in the shell. A counter force arm assembly is mounted at the tail of the shell and closely connected with the shell through inner teeth and outer teeth. The hollow hydraulic spinner is suitable for being used in a petroleum drilling blowout preventer; all the parts of the spinner are made of high-strength aluminum-titanium alloys, so that the weight is low, the appearance is small, and the spinner can adapt to fastening and loosening of nuts and bolts in narrow space; and fastening torque can be controlled by controlling hydraulic pressure during fastening.