A motor including a motor unit including a stator , a rotor and a rotation shaft receiving a rotary power from the rotor , and a housing accommodating the motor unit , the motor comprising: a first housing accommodating the motor unit and including a hitching rim extending from the upper inner surface of the first housing toward the center of the first housing ; a second housing interposed between the first housing and the motor unit and including a first flange unit protruded to an upper outer surface of the second housing for a space distanced from the first housing and a second flange protruded to a bottom outer surface of the second housing ; a first cover coupled to an upper surface of the first housing and the second housing ; a second cover coupled to a bottom surface of the first housing and the second housing : characterized by : a first array unit formed at a bottom surface of the first cover to array a centrality of the second housing by pressing the first flange unit to an inner surface of the first housing ; and a second array unit formed at a bottom surface of the second cover to array a centrality of the second housing by pressing the second flange unit to an inner surface of the first housing , wherein the first array unit is brought into close contact with the inner surface of the second housing , and wherein a periphery of the second array unit is brought into close contact with the inner surface of the second housing . a first housing accommodating the motor unit and including a hitching rim extending from the upper inner surface of the first housing toward the center of the first housing ; a second housing interposed between the first housing and the motor unit and including a first flange unit protruded to an upper outer surface of the second housing for a space distanced from the first housing and a second flange protruded to a bottom outer surface of the second housing ; a first cover coupled to an upper surface of the first housing and the second housing ; a second cover coupled to a bottom surface of the first housing and the second housing : characterized by : a first array unit formed at a bottom surface of the first cover to array a centrality of the second housing by pressing the first flange unit to an inner surface of the first housing ; and a second array unit formed at a bottom surface of the second cover to array a centrality of the second housing by pressing the second flange unit to an inner surface of the first housing , wherein the first array unit is brought into close contact with the inner surface of the second housing , and wherein a periphery of the second array unit is brought into close contact with the inner surface of the second housing . a first array unit formed at a bottom surface of the first cover to array a centrality of the second housing by pressing the first flange unit to an inner surface of the first housing ; and a second array unit formed at a bottom surface of the second cover to array a centrality of the second housing by pressing the second flange unit to an inner surface of the first housing , wherein the first array unit is brought into close contact with the inner surface of the second housing , and wherein a periphery of the second array unit is brought into close contact with the inner surface of the second housing . <EOS>