Abstract:
A method of manufacturing a motor includes coupling a base cover to a sleeve having a penetration hole formed therein, such that one side of the penetration hole is closed; inserting a shaft in the penetration hole; coupling a plate to the shaft such that the shaft is inserted in the plate; and pressing and coupling a hub to the shaft such that the shaft is inserted in the hub while the base cover is supported in an axial direction of the shaft to the base cover by using a jig, wherein the base cover is elastically deformed to make contact with the shaft. In the method of manufacturing the motor, the jig is used to deform the base cover so as to come in contact with the shaft, thereby applying the support load in the axial direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional and claims priority to U.S. application Ser. No. 11/882,588, filed Aug. 2, 2007, which has been abandoned, which in turn claims the benefit of Korean Patent Application No. 10-2006-0074555 filed with the Korean Intellectual Property Office on Aug. 8, 2006, the disclosures of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     1. Field 
     The claimed invention relates to a motor manufacturing method. 
     2. Description of the Related Art 
     In general, a motor, especially a spindle motor, is used to operate the rotating polygonal mirror of a laser printer or the disk of a hard disk drive, etc. That is, various rotational bodies may be fixed as necessary to the outer perimeter of the hub. For example, in the case of an LSU (laser scanning unit), a rotating polygonal mirror may be installed, while in the case of a hard disk drive, a disk may be installed. 
       FIG. 1  is a cross-sectional view illustrating the structure of a motor according to prior art. In the case of the motor illustrated in  FIG. 1 , while pressing on the hub  60  for the coupling of the shaft  10  inserted in the sleeve  30  with the hub  60 , the force is concentrated on the portion where the shaft  10  and plate  50  are coupled, causing a risk of mechanical damage. 
     However, if the hub is pressed with a load relatively less than that which causes mechanical damage, a sufficient load may not be applied, and as the gaps between components, etc., deviate further from the designed dimensions, problems may occur as the motor cannot perform operations in a stable manner. 
     SUMMARY 
     An aspect of the claimed invention is to provide a motor having high precision with less deviation from the designed dimensions, using a base cover made of an elastically deformable material that can be made to touch the shaft by pressing. 
     Also, an aspect of the claimed invention is to provide a method of manufacturing a motor with which deviations from the designed dimensions can be minimized, by coupling a hub onto a shaft by pressing such that the shaft is inserted, while supporting a base cover in the axial direction of the shaft. 
     One aspect provides a motor which includes a stationary member, a rotating member coupled to the stationary member which rotates about an imaginary rotational axis, and a base cover which covers one side of the stationary member and the rotating member, where the base cover is made of a material which can be elastically deformed by pressing to touch the stationary member or the rotating member. 
     The stationary member may include a sleeve in which a penetration hole is formed, and the rotating member may include a shaft which is inserted in the penetration hole. 
     A donut-shaped plate may additionally be included, which has a first hole corresponding to the cross-section of the shaft, and which is coupled with the shaft, such that the shaft is inserted in the first hole, and mounted on the other side of the sleeve. Also, a cap may additionally be included, which covers at least a portion of the plate and which is mounted on one side of the sleeve. 
     The base cover may have a shape corresponding to the shape of one side of the stationary member or the rotating member, and a ledge may be formed on the stationary member or on the rotating member such that one side is sunken in or protruded out. 
     Another aspect provides a method of manufacturing a motor which includes coupling a base cover to a sleeve, in which a penetration hole is formed, such that one side of the penetration hole is closed; inserting a shaft in the penetration hole; coupling a plate to the shaft, such that the shaft is inserted in the plate; and pressing and coupling a hub to the shaft, such that the shaft is inserted in the hub, while the base cover is supported in an axial direction of the shaft. 
     The pressing and coupling of the hub may include applying a particular support load such that the base cover is elastically deformed, where the support load may be a load corresponding to a deforming amount for the base cover to touch the shaft. 
     An operation of coupling a cap to the sleeve such that the plate is covered by the cap may further be included, between the coupling of the plate and the pressing and coupling of the hub. 
     Also, an operation of forming a fluid bearing in the gap between the sleeve and the shaft and in the gap between the shaft and the base cover may further be included. 
     Additional aspects and advantages of the present invention will become apparent and more readily appreciated from the following description, including the appended drawings and claims, or may be learned by practice of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a cross-sectional view illustrating the structure of a motor according to prior art; 
         FIG. 2  is a cross-sectional view illustrating the structure of a motor according to a first embodiment; 
         FIG. 3  is a cross-sectional view illustrating the structure of a motor according to a second embodiment; 
         FIG. 4  is a cross-sectional view illustrating the structure of a motor according to a third embodiment; 
         FIG. 5  is a cross-sectional view illustrating the structure of a motor according to a fourth embodiment; 
         FIG. 6  is a flowchart illustrating a method of manufacturing a motor according to an embodiment; 
         FIG. 7  is a cross-sectional view illustrating a process in the method of manufacturing a motor of  FIG. 6 ; and 
         FIG. 8  is a cross-sectional view illustrating the deforming of the cover according to the process of  FIG. 7   
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The motor and manufacturing method thereof according to certain embodiments of the invention will be described below in more detail with reference to the accompanying drawings, in which those components are rendered the same reference number that are the same or are in correspondence, regardless of the figure number, and redundant explanations are omitted. 
     In general, a motor consists basically of a rotating member, a stationary member that supports the rotating motion of the rotating member, and a bearing placed between the rotating member and the stationary member. For example, the rotating member may be a coupled body including a shaft, a hub coupled to and rotating together with the shaft, and a plate, etc., and the stationary member may be a sleeve, etc., surrounding the shaft. 
     However, the rotating member and the stationary member are not determined by the components per se, but are determined by their designed functions. That is, there may be cases where the shaft is fixed and the sleeve surrounding the shaft is rotated, in which case the shaft may become the stator and the sleeve may become the rotor. 
     In the embodiments of the invention described below, the descriptions will be set forth for the cases where the sleeve acts as the stationary member and the shaft and the plate and hub coupled to the shaft serve act as the rotating member. However, it is to be appreciated that the embodiments of the claimed invention are not thus limited. 
       FIG. 2  is a cross-sectional view illustrating the structure of a motor according to a first disclosed embodiment of the invention. In  FIG. 2  are illustrated a shaft  110 , base cover  120 , sleeve  130 , cap  140 , plate  150 , hub  160 , and reservoir  170 . 
     The motor according to this embodiment may be coupled to the sleeve  130  from the other side of the shaft  110  to cover the penetration hole, where the base cover  120  may be made of an elastically deformable material that can be made to touch the shaft  110  by pressing. 
     The shaft  110  may be the central axis for rotational motion, and may rotate together as a single body with the hub  160  described later. The shaft  110  may be inserted into the penetration hole  139  of the sleeve  130  described below. 
     The sleeve  130  may cover the outer perimeter of the shaft  110  to maintain stable rotating movement of the shaft  110 . A penetration hole  139  is formed in the sleeve  130  through which the shaft  110  may be inserted, and as the shaft  110  is inserted in the penetration hole  139  and covered, the shaft  110  may be supported by the sleeve  130  during the rotating movement. 
     A ledge  131  may be formed on the sleeve  130  such that the other side, to which the base cover  120  is coupled, is sunken in. Conversely, a ledge  131 ′ may be formed such that the other side, to which the base cover  120  is coupled, is protruded out. The base cover  120  may be formed to be in correspondence with the shape of this other side of the sleeve  130 . 
     Referring to  FIGS. 2 and 3 , it is seen that a ledge  131  is formed such that the other side of the sleeve  130 , to which the base cover  120  is coupled, is sunken in. Correspondingly, the base cover  120  is formed with a shape such that makes the outer perimeter of the base cover  120 ,  120   a  be covered by the ledge  131 . This may allow convenient coupling of base cover  120  with the sleeve  130 , and may also provide secure coupling. 
       FIG. 3  is a cross-sectional view illustrating the structure of a motor according to a second disclosed embodiment of the invention. In the case of the embodiment shown in  FIG. 3 , as the base cover  120   a  may be shaped as a flat plate without any curving, not only can the coupling of the base cover and the sleeve be made easier, but also the processing and manufacture of the base cover can be made simpler. 
     With regards another embodiment, in  FIG. 4 , it is seen that a ledge  131 ′ is formed such that the one side of the sleeve  130 ′, to which the base cover  120   b  is coupled, is protruded out. Curves  122  are formed at the end portion of the base cover  120   b  in correspondence to such a shape of the sleeve  130 ′, whereby the base cover  120   b  has a shape that allows it to cover the ledge  131 ′ of the sleeve  130 ′. This offers a more convenient way of coupling the base cover  120   b  and sleeve  130 ′, as well as a more secure coupling. A radial bearing, described below, may be placed in the gap between the sleeve  130  and the shaft  110 . 
     The radial bearing  174  may be a fluid bearing, which may be placed in the gap between the sleeve  130  and the shaft  110 , and may support the shaft  110  during the rotating movement of the shaft  110  to maintain stable rotating movement of the shaft  110 . 
     The radial bearing  174  may be formed by injecting oil in the gap between the shaft  110  and sleeve  130 . However, while oil is suggested in this embodiment for forming the radial bearing  174 , it is apparent that various alternatives may be used according to design requirements. 
     The base cover  120  may cover the penetration hole  139  on the other side of the shaft  110 . The base cover  120  may be coupled to the sleeve  130 , and by forming the base cover  120  to have a shape that is in correspondence with the shape of the side of the sleeve  130  to which the base cover  120  is coupled, a more secure coupling may be obtained. 
     In addition, the base cover  120  may be made with a material that can be elastically deformed. Thus, during the assembly of a motor according to this embodiment, the shaft  110  can be inserted into the penetration hole  139  of the sleeve  130  easily and with precision, by applying a support load on the base cover  120 . This will be described later in more detail. 
     A reservoir is formed in the gap between the base cover  120  and the sleeve  130 , a description of which is provided below. 
     The reservoir  170  may be formed in the gap between the base cover  120  and the sleeve  130  to house oil, and by itself may act as a bearing that supports one side of the shaft. The reservoir  170  may be connected with the radial bearing  174  described above, to supply oil to the radial bearing. That is, the gap between the sleeve  130  and base cover  120  and the gap between the sleeve  130  and shaft  110  may be contiguous with each other, and the oil injected in each may flow freely and circulate. 
     The plate  150  may have the shape of a donut having a first hole in the center that is in correspondence with the cross-section of the shaft  110 . The shaft  110  may be inserted and coupled in the first hole, and one side of the plate  150  may be mounted on one side of the sleeve  130 . 
     While the plate  150  may be manufactured separately and then coupled with the shaft  110 , the plate  150  may also be manufactured as a single body with the shaft  110  from the beginning of its manufacture, and may undergo rotating motion in accordance with the shaft  110  when the shaft  110  is rotated. A thrust bearing  171 , which will be described below, may be interposed in the gap between the plate  150  and the sleeve  130 . 
     The thrust bearing  171  may be a fluid bearing, which may be placed in the gap between the plate  150  and the sleeve  130 . The thrust bearing  171  may support the plate  150 , and may reduce friction between the plate  150  and the sleeve  130  to allow stable movement. 
     The thrust bearing  171  may be formed by injecting oil in the gap between the plate  150  and the sleeve  130 , and may be connected with the radial bearing  174  described above. That is, the gap between the plate  150  and the sleeve  130  may be contiguous with the gap between the sleeve  130  and the shaft  110 , and the oil injected in each may flow freely and circulate around the bearings. 
     Thus, the thrust bearing  171 , the radial bearing  174 , and the reservoir  170  may all be connected. While oil is suggested in this embodiment for forming the thrust bearing  171 , it is apparent that various alternatives may be used according to design requirements. 
     The cap  140  may cover the outer perimeter and one side of the plate  150  to form a bearing space with the outer perimeter part  145  of the plate  150 , and may be mounted on one side of the sleeve  130 . A more secure coupling may be obtained by forming the cap  140  to have a shape that is in correspondence with the shape of the side of the sleeve  130  on which the cap  140  is mounted. Also, a cap bearing  173  may be placed in the bearing space confined by the outer perimeter part  145  of the plate  150  and the cap. 
     The cap bearing  173  may be a fluid bearing, which may be formed by injecting oil in the bearing space, and may be connected with the thrust bearing  171  described above. That is, the gap between the plate  150  and the sleeve  130  may be contiguous with the bearing space, and the oil injected in each may flow freely and circulate around the bearings. The cap bearing  173  may support the outer perimeter and the one side of the plate  150 , and may maintain stable rotating movement of the plate  150 . 
     The hub  160  may be coupled to one side of the shaft  110  and may be formed to extend in a direction perpendicular to the axis of the shaft  110 . The hub  160  may receive driving power from a driving power generator composed of permanent magnets (not shown) and electromagnet parts (not shown), etc., to undergo rotating motion, at which the shaft  110  may also be made to undergo rotating motion in accordance with to the rotation of the hub  160 . 
     While a set of permanent magnets (not shown) and electromagnet parts (not shown) formed adjacent to the permanent magnets coupled to the hub  160  has been suggested as a driving power generator, it is apparent that the components of the driving power generator and the coupling location of each component may be varied according to design requirements. For example, a first set of electromagnets may be coupled to the hub, with a second set of electromagnets coupled adjacent to the first electromagnets. 
     Various rotational bodies may be coupled to the outer perimeter of the hub  160 , as necessary. For example, in the case of an LSU (laser scanning unit), a rotating polygonal mirror may be coupled, while in the case of a hard disk drive, a disk may be coupled. 
     As described above, the sleeve  130  may cover the outer perimeter of the shaft  110  to maintain stable rotating movement of the shaft  110 . A penetration hole  139  is formed in the sleeve  130  through which the shaft  110  may be inserted, and as the shaft  110  is inserted in the penetration hole  139  and covered, the outer perimeter of the shaft  110  may be supported by the sleeve  130  during the rotating movement. 
     A convenient and secure manner of coupling may be obtained by forming a ledge  131  on the sleeve  130 , such that the side to which the base cover  120  is coupled is sunken in, and forming the base cover to be in correspondence with such a shape of the sleeve  130 . 
     Moreover, a convenient and secure manner of coupling may be obtained by forming a ledge  131 ′ on the sleeve  130 , such that the side to which the base cover  120  is coupled is protruded out, and forming the base cover to be in correspondence with the shape of the sleeve  130 . 
     In a predetermined position on the sleeve  130 , a contiguous hole (not shown) may be formed that connects the thrust bearing  171  and the reservoir  170 . The oil forming the thrust bearing  171  and the oil forming the reservoir  170  may adequately circulate through the contiguous hole (not shown), whereby not only can the pressure created in each fluid bearing within the motor be made uniform, but also bubbles, etc., can be moved by the circulation so that they may readily be released. 
     While in certain embodiments of the claimed invention described above, a structure is described in which the plate  150  and the base cover  120  are coupled on different sides of the sleeve  130 , the plate  250  and the base cover  220  may just as well be coupled on the same side, as illustrated in  FIG. 5 . Here, with reference to  FIG. 5 , a sunken portion may be formed on the side of the sleeve  230  adjacent to the plate  250 , that is in correspondence with the shape of the plate  250 , for housing the plate  250 . 
     As set forth above, a motor according to an embodiment of the claimed invention may have a base cover that covers one side of the rotating member and stationary member, where the base cover may be made of a material capable of elastic deforming, so that a support load may be applied from the side of the base cover to provide a secure coupling and manufacture. Thus, it is apparent that various embodiments may be obtained by changing, as necessary, the rotating member or stationary member, besides the base cover made of an elastically deformable material. 
     Next, a method will be described of manufacturing a motor according to an embodiment of the claimed invention.  FIG. 6  is a flowchart illustrating a method of manufacturing a motor according to an embodiment of the invention. 
     Operation S 1  is that of coupling the base cover  120  to the sleeve  130  to close one side of the penetration hole. The shape of the coupling surface of the sleeve  130  and the corresponding shape of the base cover  120  may be varied for easier coupling of the base cover  120  and sleeve  130 , and examples of which may be found in the shapes of the coupling surface of the sleeve  130  and the base cover  120  illustrated in  FIGS. 2 to 5 . 
     Operation S 2  is that of inserting the shaft  110  in the penetration hole, where the shaft may be inserted in the penetration hole by positioning the shaft at a position that is in correspondence with the penetration hole, and by pressing on a surface of the shaft. Thus, the shaft  110  may be covered by the sleeve  130 . 
     Operation S 3  is that of coupling the plate  150  to the shaft  110 , so that the shaft  110  may be inserted in the first hole of the plate  150 . This allows the plate  150  to undergo rotating motion according to the rotation of the shaft  110  and to be supported by the sleeve  130  on which the plate  150  is mounted. 
     While operation S 3  may be performed after operation S 2 , operation S 2  may just as well be performed after operation S 3 . In other words, the order of the operations described above may be varied as necessary. 
     Operation S 4  is that of coupling the cap  140  to the sleeve  130 . As described with regards the motor described above, the cap  140  is a component that may cover the outer perimeter and one side of the plate  150  to form a bearing space with the outer perimeter part  145  of the plate  150 , and may be mounted on one side of the sleeve  130 . Thus, by coupling the cap  140  to the sleeve  130 , the coupling relationship between the plate  150  and sleeve  130  may be made secure, and by the subsequent coupling of the hub, an even stronger coupling relationship may be obtained. 
     Operation S 5  is of pressing and coupling the hub  160  to the shaft  110  such that the shaft  110  is inserted in the hub  160 , while applying a particular support load in the axial direction of the shaft  110 , such that the base cover  120  is elastically deformed, and supporting the base cover  120 . This will be described in more detail with reference to  FIGS. 7 and 8 . 
       FIG. 7  is a cross-sectional view illustrating a process in the method of manufacturing a motor of  FIG. 6 , and  FIG. 8  is a cross-sectional view illustrating the deforming of the cover according to the process of  FIG. 7 . In  FIGS. 7 and 8  are illustrated a shaft  110 , base cover  120 , sleeve  130 , cap  140 , plate  150 , hub  160 , and jig  180 . 
     In a method of manufacturing a motor according to this embodiment, when performing the process of pressing the hub  160  so as to couple the shaft  110  and the hub  160 , as illustrated in  FIG. 7 , a particular support load may be applied by the jig  180  in the axial direction of the shaft  110  so that the base cover  120  undergoes elastic deforming. Thus, the base cover  120  may be deformed within the range of elastic deforming to touch a side of the shaft  110 , which adds to the load on the shaft  110  to complement the pressure applied on the hub  160 . In this way, the amount of pressure applied on the hub  160  may be reduced, and the force concentrated on the portion where the shaft  110  and the plate are coupled may also be reduced, to resolve some of the problems of prior art described above. 
     When the support load applied by the jig  180  is removed after the coupling of the hub  160  and shaft  110  is complete, the base cover  120  may recover its shape before deforming by means of the elastic force of the base cover  120  itself. Thus, the dimensions considered in the design stages may be ensured, and deviations that may occur during manufacture may be minimized. 
       FIG. 8  is a cross-sectional view illustrating the deforming of the cover according to the process of  FIG. 7 , where drawing (a) illustrates the base cover  120  before applying a support load, drawing (b) illustrates the base cover  120  while the support load is being applied by the jig  180 , and drawing (c) illustrates the base cover  120  that has recovered its shape before deforming, after the support load has been removed. The deforming of the base cover  120  described above may be observed in the drawings (a) to (c) of  FIG. 8 . 
     In designing the base cover  120 , an additional operation may be included of determining elasticity factors (for example, thickness or material) of the base cover  120  in consideration of the support load applied by the jig  180 , and the gap between the base cover  120  and the sleeve  130 , etc. Also, an additional operation may also be included of determining the magnitude of the support load applied by the base cover, in consideration of the elasticity factors of the base cover. A method such as the FEM (finite element method) may be used. 
     As set forth above, with a motor and a method of manufacturing the motor according to certain aspects of the invention, deviations from the designed dimensions may be reduced to provide improved precision, by using a base cover made of an elastically deformable material that can be made to touch the shaft by pressing. 
     While the spirit of the invention has been described in detail with reference to particular embodiments, the embodiments are for illustrative purposes only and do not limit the invention. In addition, numerous embodiments besides those set forth above are encompassed in the claimed invention. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the invention.