Preloading adjustment-free device, tire mold and mounting device

The utility model discloses a preloading adjustment-free device, a tire mold and a mounting device, and belongs to the field of tire molds, the preloading adjustment-free device comprises a lower base plate, a locking hole is formed in the center of the lower base plate, a connecting column is arranged in the locking hole, and the bottom of the connecting column is rotatably locked with the locking hole; an elastic piece is arranged on the lower base plate and arranged on the connecting column in a sleeving mode at the same time. The motor further comprises an end cover with a hole, the end cover with the hole is arranged above the elastic piece, a boss is arranged on the top of the connecting column, and the end cover with the hole overcomes the elastic force of the elastic piece through the boss on the top of the connecting column. The upper end and the lower end of the preloading adjustment-free device abut against the middle sleeve and the upper ring respectively, the installation device comprises a base,