Lengthened head structure of spindle of double-faced vehicle

The utility model provides a lengthened head structure of a spindle of a double-faced vehicle, which comprises a main spindle box and a lengthened head, wherein a rotating spindle is arranged in the main spindle box, the main spindle box comprises a box body and clamping mechanisms which are arranged at two ends of the box body and can perform radial clamping or releasing for loading and unloading with the box body, two ends of the lengthened head are detachably connected with the main spindle box and the clamping mechanisms, a lengthened shaft matched with the rotating spindle of the main spindle box is arranged in the lengthened head, and two ends of the lengthened shaft are respectively connected with the rotating spindle and the clamping mechanisms. When parts which are in different shaft lengths and ready to be processed are processed by the double-faced vehicle, the parts which are in the larger shaft lengths and ready to be processed can be processed by selecting the lengthened heads in different sizes