A motor comprising: a housing that includes: a bottom portion on which a first bearing accommodating portion is formed; and a cylindrical side surface portion which extends from an edge of the bottom portion; a rotor assembly that includes: a rotation shaft; and a rotor which is mounted on an outer circumferential surface of the rotation shaft and is accommodated in an inside portion of the housing; a stator assembly that is accommodated in an inside portion of the housing and surrounds the rotor; a housing cover that is coupled to an upper end of the housing; a flow guide that is seated on the upper side of the housing cover; an impeller that is connected to the rotation shaft at an upper side of the flow guide; an impeller cover that covers the impeller; a first bearing that is accommodated in the first bearing accommodating portion and into which one end portion of the rotation shaft is inserted; and a second bearing that is accommodated in the second bearing accommodating portion and into which the other end of the rotation shaft is inserted, wherein the housing cover includes: a cover body on which an opening portion is formed therein; a second bearing accommodating portion at a central portion thereof; a plurality of connection arms that connect the second bearing accommodating portion and the cover body; and a guide rib that extends from an edge of the opening portion of the cover body, wherein the guide rib extends by a predetermined length in a direction orthogonal to a radial direction of the cover body from an edge of the opening portion of the cover body, characterised in that the guide rib is formed in a circular sleeve shape along the edge of the opening portion of the cover body. a housing that includes: a bottom portion on which a first bearing accommodating portion is formed; and a cylindrical side surface portion which extends from an edge of the bottom portion; a bottom portion on which a first bearing accommodating portion is formed; and a cylindrical side surface portion which extends from an edge of the bottom portion; a rotor assembly that includes: a rotation shaft; and a rotor which is mounted on an outer circumferential surface of the rotation shaft and is accommodated in an inside portion of the housing; a rotation shaft; and a rotor which is mounted on an outer circumferential surface of the rotation shaft and is accommodated in an inside portion of the housing; a stator assembly that is accommodated in an inside portion of the housing and surrounds the rotor; a housing cover that is coupled to an upper end of the housing; a flow guide that is seated on the upper side of the housing cover; an impeller that is connected to the rotation shaft at an upper side of the flow guide; an impeller cover that covers the impeller; a first bearing that is accommodated in the first bearing accommodating portion and into which one end portion of the rotation shaft is inserted; and a second bearing that is accommodated in the second bearing accommodating portion and into which the other end of the rotation shaft is inserted, wherein the housing cover includes: a cover body on which an opening portion is formed therein; a second bearing accommodating portion at a central portion thereof; a plurality of connection arms that connect the second bearing accommodating portion and the cover body; and a guide rib that extends from an edge of the opening portion of the cover body, wherein the guide rib extends by a predetermined length in a direction orthogonal to a radial direction of the cover body from an edge of the opening portion of the cover body, characterised in that the guide rib is formed in a circular sleeve shape along the edge of the opening portion of the cover body. a cover body on which an opening portion is formed therein; a second bearing accommodating portion at a central portion thereof; a plurality of connection arms that connect the second bearing accommodating portion and the cover body; and a guide rib that extends from an edge of the opening portion of the cover body, wherein the guide rib extends by a predetermined length in a direction orthogonal to a radial direction of the cover body from an edge of the opening portion of the cover body, characterised in that the guide rib is formed in a circular sleeve shape along the edge of the opening portion of the cover body.