Dumbbell structure with dumbbell heads convenient to replace

The dumbbell structure comprises a handle, the dumbbell heads and a locking mechanism, a connecting groove is formed in one side of the handle, one end of each dumbbell head is arranged in the connecting groove, each dumbbell head comprises an iron core and a dumbbell ring, one end of each iron core is in sliding connection with the corresponding connecting groove, and the other end of each iron core is in sliding connection with the corresponding dumbbell ring. One end of the iron core is provided with a dumbbell ring, the other end of the iron core is provided with a dumbbell ring, the locking mechanism is arranged on the handle and the iron core, the locking mechanism is composed of a plurality of through holes, a fixing ring, a first spring, a sliding piece, a limiting pin and a limiting groove, the plurality of through holes are formed in the handle, the fixing ring is arranged in the through holes in the handle, and the first spring is arranged in the limiting groove. A first spring is arranged on the s