Hydraulic automatic inner mold retracting and releasing device for prefabricated box girder

The utility model belongs to the field of expressway precast box girder forming die equipment, and relates to a hydraulic automatic inner die retracting and releasing device for a precast box girder, which adopts an integral foldable stainless steel die, and after concrete of a girder body reaches the standard, a hydraulic telescopic rod supported by an inner top die retracts to drive the inner top die to retract downwards from the center. And the hydraulic telescopic rod supported by the inner bottom die is retracted to drive the inner bottom die to be retracted upwards from the center, meanwhile, the hydraulic telescopic rod of the walking mechanism extends downwards to the beam bottom, and after the pulleys make contact with the bottom and are stressed, the hydraulic telescopic rod of the walking mechanism is retracted to drive the inner side die to be retracted towards the center, and folding of the inner die is completed. After the inner mold is folded, the winch outside the box girder works, the central