A rotor for being disposed within a stator of a motor, said rotor comprising: a sleeve formed with a shaft hole to be coupled with a motor shaft; a plurality of rotor cores arranged to be spaced apart from one another in a circumferential direction of the rotor, to define a plurality of rotor slots, one or more of the rotor cores having through holes, respectively; a plurality of bridges arranged to connect the rotor cores to the sleeve, respectively; a plurality of permanent magnets respectively inserted into the rotor slots such that at least one of the permanent magnets has an inner end spaced apart from the sleeve; a plurality of inner support protrusions extending from the sleeve toward the rotor slots, to support the inner ends of the permanent magnets, respectively; a plurality of outer support protrusions extending from the rotor cores, to support the outer ends of the permanent magnets, respectively; characterized by an injection-molded plastic member filling the rotor slots, to cover the outer ends of the permanent magnets; a plurality of fixing grooves provided at the rotor cores, respectively, to receive the injection-molded plastic member; and a plurality of fixing protrusions arranged outside the fixing grooves in a radial direction of the rotor, respectively, to prevent the injection-molded plastic member from being separated from the rotor by centrifugal force during rotation of the rotor. a sleeve formed with a shaft hole to be coupled with a motor shaft; a plurality of rotor cores arranged to be spaced apart from one another in a circumferential direction of the rotor, to define a plurality of rotor slots, one or more of the rotor cores having through holes, respectively; a plurality of bridges arranged to connect the rotor cores to the sleeve, respectively; a plurality of permanent magnets respectively inserted into the rotor slots such that at least one of the permanent magnets has an inner end spaced apart from the sleeve; a plurality of inner support protrusions extending from the sleeve toward the rotor slots, to support the inner ends of the permanent magnets, respectively; a plurality of outer support protrusions extending from the rotor cores, to support the outer ends of the permanent magnets, respectively; characterized by an injection-molded plastic member filling the rotor slots, to cover the outer ends of the permanent magnets; a plurality of fixing grooves provided at the rotor cores, respectively, to receive the injection-molded plastic member; and a plurality of fixing protrusions arranged outside the fixing grooves in a radial direction of the rotor, respectively, to prevent the injection-molded plastic member from being separated from the rotor by centrifugal force during rotation of the rotor. a plurality of bridges arranged to connect the rotor cores to the sleeve, respectively; a plurality of permanent magnets respectively inserted into the rotor slots such that at least one of the permanent magnets has an inner end spaced apart from the sleeve; a plurality of inner support protrusions extending from the sleeve toward the rotor slots, to support the inner ends of the permanent magnets, respectively; a plurality of outer support protrusions extending from the rotor cores, to support the outer ends of the permanent magnets, respectively; characterized by an injection-molded plastic member filling the rotor slots, to cover the outer ends of the permanent magnets; a plurality of fixing grooves provided at the rotor cores, respectively, to receive the injection-molded plastic member; and a plurality of fixing protrusions arranged outside the fixing grooves in a radial direction of the rotor, respectively, to prevent the injection-molded plastic member from being separated from the rotor by centrifugal force during rotation of the rotor.