A motor comprising: a stator and a rotor comprising a hole in which a shaft is disposed; wherein the rotor further comprising a rotor core; a plurality of magnets arranged on a radially outer circumferential surface of the rotor core; and a cover disposed on a radially outer circumferential surface of the plurality of magnets, wherein the rotor core comprises a plurality of guide protrusions disposed on the radially outer circumferential surface of the rotor core between the plurality of magnets, and wherein a distance from a center of the rotor core to a radially outer circumferential surface of the cover through a center of the guide protrusion is smaller than a distance from the center of the rotor core to the radially outer circumferential surface of the magnet through a center of one of the plurality of magnets, wherein the cover is a can member, wherein the can member comprises a separate first can and a separate second can, each one disposed along an axial direction of the shaft respectively at one end side of the rotor core, characterized in that the first can and the second can are arranged such that a bottom end of a groove portion of the first can which bottom end concavely formed on the outer circumferential surface of the rotor core and disposed between the magnets, comes into contact with a bottom end of a groove portion of the second can which bottom end concavely formed on the outer circumferential surface of the rotor core and disposed between the magnets, and in that the first can and the second can comprise a first weld bead disposed through the bottom end of said groove portion of the first can and the bottom end of said groove portion of the second can. a stator and a rotor comprising a hole in which a shaft is disposed; wherein the rotor further comprising a rotor core; a plurality of magnets arranged on a radially outer circumferential surface of the rotor core; and a cover disposed on a radially outer circumferential surface of the plurality of magnets, a rotor core; a plurality of magnets arranged on a radially outer circumferential surface of the rotor core; and a cover disposed on a radially outer circumferential surface of the plurality of magnets, wherein the rotor core comprises a plurality of guide protrusions disposed on the radially outer circumferential surface of the rotor core between the plurality of magnets, and wherein a distance from a center of the rotor core to a radially outer circumferential surface of the cover through a center of the guide protrusion is smaller than a distance from the center of the rotor core to the radially outer circumferential surface of the magnet through a center of one of the plurality of magnets, wherein the cover is a can member, wherein the can member comprises a separate first can and a separate second can, each one disposed along an axial direction of the shaft respectively at one end side of the rotor core, characterized in that the first can and the second can are arranged such that a bottom end of a groove portion of the first can which bottom end concavely formed on the outer circumferential surface of the rotor core and disposed between the magnets, comes into contact with a bottom end of a groove portion of the second can which bottom end concavely formed on the outer circumferential surface of the rotor core and disposed between the magnets, and in that the first can and the second can comprise a first weld bead disposed through the bottom end of said groove portion of the first can and the bottom end of said groove portion of the second can.