A motor includes a housing that has a bottom with a first bearing accommodation and a cylindrical side surface portion which extends from the bottom; a rotor assembly with a rotation shaft, and a rotor mounted on the rotation shaft and accommodated inside the housing; a stator assembly accommodated inside the housing and surrounding the rotor; a housing cover coupled to an upper end of the housing and having a second bearing accommodation; a flow guide on the housing cover; an impeller connected to the rotation shaft over the flow guide; an impeller cover; a first bearing accommodated in the first bearing accommodation and receiving the rotation shaft; and a second bearing accommodated in the second bearing accommodation and receiving the rotation shaft, the housing cover having a cover body with an opening, connection arms between the second bearing accommodation and the opening portion, and a guide rib.