Electromagnetic belt pulley

The utility model discloses an electromagnetic belt pulley, comprising a belt pulley, a hub, an armature, a shaft sleeve and an electromagnet. The electromagnetic belt pulley is characterized in that the belt pulley and the hub are fixed by bolts, the hub is movably connected with the shaft sleeve by a bearing, the armature is connected with the hub by a leaf spring, a coiled spring is installed between the hub and the armature, one end of the coiled spring is connected with the armature and the other end props against the shaft sleeve, and the electromagnet is installed at one side of the armature; when the belt pulley drives the hub to rotate, the armature is attached on one side of the hub and rotated along the hub under the effect of the leaf spring; when in rotating, the coiled spring is expanded to be tightly connected with the armature, the other end of the coiled spring pushes the shaft sleeve to rotate; after the electromagnet is electrified, the armature is absorbed and cannot rotate, thus the coile