Combined backlash-free precise large-torque rotary table

The invention discloses a combined backlash-free precise large-torque rotary table, which comprises a base, wherein a box body shell, a first-stage box body, a second-stage box body and a rotary table stand column are fixed to the base, a motor is arranged on one side of the first-stage box body, a first-stage worm which is in transmission connection with the motor and is horizontally arranged is fixed in the first-stage box body, the first-stage worm is rotationally connected with a variable-tooth-thickness involute worm wheel installed on the first-stage box body, the variable-tooth-thickness involute worm wheel is rotationally connected with a second-stage worm fixed to the second-stage box body, a rotary table bearing is fixedly arranged on the upper end face of the rotary table stand column, a workbench is arranged on the rotary table bearing in a sleeving mode, pin rollers are arranged on the lower end face of the workbench at equal intervals in the circumferential direction, and the left and right enve