Stator, motor and record medium drive apparatus and method of fabricating stator

A stator includes a base board, a plurality of coil patterns patterned on one face of the base board, a stator core having a ring-like portion formed in a ring-like shape, a plurality of teeth base ends of which are fixed to the ring-like portion and front end portions formed respectively at front ends of the plurality of teeth in which the coil patterns and the teeth are laminated onto the base board to be respectively opposed to each other, and covers having base members bonded to the base board in a state of being respectively fitted to the plurality of teeth and covering surroundings of the respective teeth and conductive patterns patterned to inner faces of the base members and electrically connected to the coil patterns.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a stator constituting a stator of a motor for driving to rotate a record medium of HD (hard disk) or the like, a motor having the stator and a record medium drive apparatus having the motor as well as a method of fabricating a stator.

2. Description of the Related Art

In recent years, an information recording/reproducing apparatus using a hard disk drive apparatus (HDD) has been started to be adopted in a portable music reproducing apparatus, a portable telephone or the like. Particularly, an information/recording reproducing apparatus of a portable type is going to constitute a main current in the future owing to its availability, and further small-sized formation and thinned formation have been requested. In accordance therewith, an improvement has been carried out for small-sized formation and thinned formation of a motor for driving HD (hard disk).

Here, a brief explanation will be given of a hard disk drive apparatus having a general motor in reference toFIG. 27throughFIG. 29. As shown byFIG. 27, the disk drive apparatus40includes a stator43having a coil41and a stator core42, and a rotor46having a permanent magnet44and a hub45. The hub45is supported by a sleeve47rotatably around an axis line L and formed with a fitting portion45afitted to a center hole of a disk D. Thereby, the hard disk D is fixed to the hub45. Further, an outer periphery of the hub45is fixed with the permanent magnet44to be opposed to the stator core42to be spaced apart from each other by a predetermined distance.

The sleeve47is fixed to a base48and rotatably supports the hub45. In this case, a more or less gap is ensured between the sleeve47and the hub45, and the gap is filled with oil W. Further, an outer surface of the hub45or the sleeve47is pertinently formed with a radial dynamic pressure generating groove and a thrust dynamic pressure generating groove, not illustrated, referred to as a herringbone groove. Thereby, when the hub45is rotated around the axis line L, the hub45is rotated stably without being fluctuated in a thrust direction and a radial direction. That is, the hub45is brought into a state of being supported by a hydraulic dynamic bearing.

As shown byFIG. 28, the stator core42includes a core back42aformed in a ring-like shape, and a plurality of teeth42bformed to extend in a radius direction. Further, the stator core42is supported by a base48on a side of the core back42a. The teeth42bare formed at respective predetermined angles around the axis line L and formed such that a number (slot number) thereof constitutes a multiple of 3. For example, the teeth42bare formed by 9 slots at respective 40 degrees. Further, the coils41are respectively wound at surroundings of the plurality of teeth42b. In this case, the coils41are wound at every 3 (spaced apart by 2) thereof to constitute 3 phases (U phase, V phase, W phase).

When the hard disk D is driven by the disk drive apparatus40constituted in this way, first, the coil41is supplied with a three phase alternating current to generate a magnetic field in the coil41. The magnetic field is operated to the permanent magnet44by way of the teeth42bto rotate the rotor around the axis line L. Thereby, the disk D fixed to the rotor46by the fitting portion45acan be rotated.

Meanwhile, as described above, further small-sized formation and thinned formation are requested for the motor in the future. However, as shown byFIG. 29, the coil41is wound at the surrounding to the tooth42bby a predetermined turn number in order to ensure a constant electromotive force, and therefore, a thickness T1is necessarily thickened. Therefore, it is difficult to achieve thinned formation as a whole. Particularly, the thickness T1of the coil41is significant in comparison with the product constituted otherwise, and therefore, the thickness T1effects a considerable influence on thinned formation. Therefore, in order to realize thinned formation, it is necessary to thin the coil41as thin as possible. However, as described above, the predetermined turn number is needed for ensuring the constant electromotive force, and therefore, the turn number of the coil41cannot simply be reduced.

Hence, although there is conceivable a method of reducing the turn number of the coil41wound per the single tooth42bby increasing the number (slot number) of the teeth42b, in this case, as shown byFIG. 28, with an increase in the slot number, a distance T2between the teeth42bis reduced. Here, in order to wind a coil wire around the tooth42b, the coil wire is normally wound there around by inserting a coiling machine between the teeth42band orbiting the coiling machine centering on the tooth42b. Therefore, when the distance T2between the teeth42bis made to be smaller than a rectified value, the coiling machine cannot be made to pass therethrough and the coil wire cannot be wound therearound. Therefore, the slot number cannot be increased to a necessary number and the number is limited. Therefore, the more amounted to the thinned formation of the total, the more difficult to thin the thickness T1by extremely reducing the turn number of the coil41for the single tooth42b.

On the other hand, there is known a disk drive apparatus achieving thinned formation as a whole by constituting a stator without mechanically winding a coil wire therearound (refer to, for example, Patent References 1 and 2).

As shown byFIG. 30andFIG. 31, the disk drive apparatus50includes a metal core board51having a function of a core and windings of a motor and a function of a wiring board mounted with a part of IC or the like. The metal core board51constitutes a stator and is constituted by a tooth connecting portion, not illustrated, a tooth coil forming portion51a, a tooth front end portion51b, a wiring51cand a through hole51d.

The tooth connecting portion is constituted by laminated plates of thin plates and formed by a ring-like shape. The tooth coil forming portion51ais a portion a base end side of which is fixed to the tooth connecting portion and which is formed by being extended to an inner side in a radius direction, and a portion in correspondence with the tooth of the background art. Normally, the tooth coil forming portion51ais formed to constitute a number of pieces 1.5 times as much as a number of poles of a permanent magnet52formed in a ring-like shape. Further, a front end of the tooth coil forming portion51aconstitutes the tooth front end portion51bto be opposed to the permanent magnet52.

The wirings51care arranged at a surface and a rear face of the tooth coil forming portion15aand is fixed by an insulating resin53. Further, the insulating resin53is formed with the through hole51dan inner face of which is plated by a metal and which electrically connects to the wirings51cformed at the surface and the rear face. At this occasion, as shown byFIG. 31, the wirings51cand the through holes51dare connected to spirally surround the tooth coil forming portions51a. Thereby, by making an electric current flow in the wiring51c, a magnetic field for rotating the permanent magnet52can be generated.

According to the disk drive apparatus50including the metal core board51constituted in this way, the stator can be constituted without winding mechanically the coil wire around the tooth as in the related art, and therefore, the number of the tooth coil forming portions51a, that is, the slot number can be increased without being conscious of the coiling machine. Therefore, the wiring51cwound at the surrounding of the single tooth coil forming portion51acan be reduced, and a thickness can be restrained as less as possible. Therefore, thinned formation as a whole can be achieved.

However, according to the related arts described in Patent References 1 and 2, the following problem still remains.

That is, since the insulating resin53is interposed between the tooth coil forming portion51aand the wiring51c, in comparison with the case of winding the coil wire, a total length thereof is prolonged. Further, the through hole51dis bored by mechanical working or laser working, and therefore, a positional shift thereof with the wiring51cis liable to be brought about. Therefore, it is difficult to arrange the through holes51dby narrow intervals and the total length is further prolonged. As a result thereof, there is brought about a drawback that an electric resistance is increased, an efficiency of the electromotive force is deteriorated and power consumption is increased.

Further, owing to a structure in which a portion of the wiring51cand the tooth coil forming portion51aare embedded at inside of the insulating resin53, there is a concern that heat generated by electricity conduction is not radiated to outside but is confined to inside. Therefore, exfoliation of a part is liable to be brought about, which amounts to a reduction in a power function and a reduction in a reliability.

In this way, even when the thinned formation can be achieved, a new drawback is brought about as a substitute therefor.

SUMMARY OF THE INVENTION

The invention has been carried out in consideration of such a situation and it is an object thereof to provide a stator capable of achieving thinned formation and achieving promotion of efficiency of an electromotive force and heat radiating performance, a motor having the stator and a record medium drive apparatus having the motor as well as a method of fabricating the stator.

The invention provides a following means in order to resolve the above-described problem.

According to the invention, there is provided a stator which is a stator arranged opposedly to a permanent magnet rotated along an axis line the stator comprising an insulating base board, a plurality of conductive coil patterns patterned onto one face of the base board at respective angles centering on the axis line, a stator core of a magnetic member including a ring-like portion formed in a ring-like shape centering on the axis line, a plurality of teeth base ends of which are fixed to the ring-like portion and which are formed to extend in a radius direction directed to the permanent magnet at the respective predetermined angles, and front end portions respectively formed at front ends of the plurality of teeth and opposed to a peripheral face of the permanent magnet, wherein the coil patterns and the teeth are laminated on the base board to be opposed to each other, an insulating layer coated on an outer surface of the stator core, and covers including insulating base members bonded to the base board in a state of being respectively fitted to the plurality of teeth laminated on the base board and covering surroundings of the respective teeth and conductive patterns patterned to inner faces of the base members and electrically connected to the coil patterns.

Further, according to the invention, there is provided a method of fabricating a stator which is a method of fabricating a stator opposedly arranged to a permanent magnet rotated around an axis line, the method comprising a base board working step of patterning a plurality of coil patterns on one face of an insulating base board at respective predetermined angles centering on the axis line by a conductive material, a stator core forming step of forming a stator core including a ring-like portion formed in a ring-like shape centering on the axis line, a plurality of teeth base ends of which are fixed to the ring-like portion and which are formed to extend in a radius direction directed to the permanent magnet at the respective angles, and front end portions respectively formed at front ends of the plurality of teeth and opposed to a peripheral face of the permanent magnet by working a flat plate of a magnetic member, a layer coating step of coating an insulating layer on an outer surface of the stator core, a base member working step of patterning a conductive pattern electrically connected to the coil pattern on an insulating base member by a conductive material and folding to form the base member in a state of constituting an inner face by the conductive pattern to thereby form a cover for surrounding a surrounding of the tooth when the base member is fitted to the tooth, a fixing step of fixing the base board and the stator core in a state of being laminated together such that the plurality of coil patterns and the plurality of teeth are opposed to each other, and a bonding step of fitting the cover to the teeth and electrically connecting the coil pattern and the conductive pattern while bonding the cover to the base board.

According to the stator and the method of fabricating the stator according to the invention, first, there is carried out the base board working step of patterning a plurality of coil patterns on one face of the base board by the conductive material of copper or the like. At this occasion, the plurality of coil patterns are patterned at the respective predetermined angles centering on the axis line in the peripheral direction of the base board.

There is carried out the stator core forming step of forming the stator at a timing the same as that of the base board working step, or a timing there before or thereafter. That is, the stator core comprising the ring-like portion and the plurality of teeth and the front end portions are formed by working a flat plate of a magnetic member of a silicon steel plate or the like. At this occasion, the plurality of teeth are formed by a number the same as that of the coil patterns at respective angles the same as the angles of forming the coil patterns. Further, after forming the stator core, the layer coating step is carried out to coat (coat) the insulating layer on the outer surface of the stator core.

Further, there is carried out the base member working step of forming the cover at timings the same as those of the respective steps or timings therebefore or thereafter. That is, the cover is formed by forming the conductive pattern by patterning the conductive material of copper or the like on the base member of polyimide or the like, thereafter, folding to form the base member by utilizing a die or the like in the state of constituting an inner side by the conductive pattern. At this occasion, the cover is formed by a size capable of fitting to cover the teeth of the stator core. Further, the plurality of covers are formed in accordance with a number of the teeth.

After all of the respective steps have been finished, first, there is carried out the fixing step of fixing the base board and the stator core. That is, after laminating the base board and the stator core such that the plurality of coil patterns and the plurality of teeth are respectively opposed to each other, the both members are fixed by adhering or the like. Thereby, there is brought about a state in which the teeth are respectively mounted on the plurality of coil patterns. Further, the stator core is brought into the laminated state in a state in which all of the ring-like portions, the teeth and the front end portions are brought into face contact with the base board.

After the fixing step has been finished, the covers are respectively fitted to the plurality of teeth laminated onto the base board. That is, the covers are fitted to cover the teeth. At this occasion, the inner face of the cover is patterned with the conductive pattern, and therefore, the conductive pattern is brought into a state of being brought into contact with the tooth. Further, after fitting the cover, the conductive pattern and the coil pattern are electrically connected while bonding the cover to the base board. By the electric connection, the coil pattern and the conductive pattern function as a coil for exciting the teeth by being spirally wound at the surrounding of the tooth.

An explanation will be given of a case of rotating the permanent magnet constituting a rotor by utilizing the stator fabricating in this way. When a predetermined current is supplied to the conductive pattern and the coil pattern, since these function as the coil, the tooth is excited to generate a magnetic field. By the magnetic field, the permanent magnet can be rotated around the axis line. Further, the stator cores respectively include the front end portions opposed to a peripheral face of the permanent magnet at front ends of the teeth, and therefore, delivery of a magnetic flux between the stator cores and the permanent magnet becomes dense. Therefore, the permanent magnet can efficiently be rotated.

Particularly, the coil pattern patterned to the baseboard and the conductive pattern patterned to the inner face of the cover can be functioned as the coil, and therefore, different from the constitution of forming the coil by mechanically winding the coil wire as in the related art, it is not necessary to use the coiling machine. Therefore, the stator core can be constituted to increase the number of teeth, that is, the slot number as much as possible. Therefore, the turn number of the coil per one tooth can be reduced and the thickness can be restrained as less as possible. Therefore, the thinned formation of the total can be achieved.

Further, the coil pattern and the conductive pattern are brought into a state of being brought into contact with the tooth by way of the insulating layer. Therefore, a wasteful gap is not formed between the coil pattern and the conductive pattern and the teeth. Therefore, after ensuring insulation between the coil pattern and the conductive pattern and the teeth, lengths of the coil pattern and the conductive pattern can be constituted by necessary minimum lengths, and an electric resistance can be restrained as less as possible. Therefore, the electromotive force can efficiently be generated and wasteful power consumption can be eliminated without reducing the reliability.

Further, one face of the stator core other than the tooth is exposed, and therefore, an exposure area exposed to the atmosphere is larger than that of the related art. Therefore, heat generated by electricity conduction can efficiently be radiated. Therefore, an operational failure or exfoliation of a part by heat or the like can be restrained from being brought about, and the reliability can be promoted.

Further, it is not necessary to utilize the coiling machine, and therefore, the gap between the contiguous front end portions can be made to be as small as possible. Therefore, a portion of a magnetic line of force flowing in the tooth can be made to flow to the contiguous tooth by way of the front end portion and the magnetic force by which the permanent magnet and the front end portion attract each other can be reduced. As a result, the cogging torque can be reduced, and the high performance formation can be achieved.

Further, the stator core is pressed to the base board by the cover after being fixed onto the baseboard over the ring-like portion, the teeth and the front end portions. Therefore, although the base end sides of the respective teeth are fixed to the ring-like portion in a cantilever state, the respective teeth are brought into a state of being connected to each other by way of the base board. Therefore, vibration of the respective teeth caused by influence of rotation of the permanent magnet can be restrained. When assumedly, the base end sides of the respective teeth are only fixed to the ring-like portions there is a concern of bringing about unnecessary vibration of fluctuating the respective teeth or the like by being influenced by rotation of the permanent magnet. However, according to the invention, such unnecessary vibration can be restrained as less as possible. Therefore, strange sound or the like can be eliminated as less as possible and durability can be promoted.

Further, according to the stator of the invention, there is provided the stator of the invention, wherein a pattern of one of the coil pattern or the conductive pattern is patterned such that respective electrically independent single pieces of wirings are aligned at constant intervals in the radius direction in a state of being skewed to the radius direction directed to the permanent magnet, the other pattern is patterned such that respective electrically independent single pieces of wirings are aligned at constant intervals to the radius direction in a state of being orthogonal to the radius direction directed to the permanent magnet, and both ends of respective wirings of the other pattern are electrically connected respectively to one ends and other ends of contiguous wirings of wirings of the one pattern.

Further, according to the method of fabricating the stator of the invention, there is provided the method of fabricating the stator of the invention, wherein in carrying out the base board working step and the base member working step, either one pattern of the coil pattern and the conductive pattern is formed by patterning the pattern such that respective electrically independent single pieces of wirings are aligned at constant intervals to the radius direction in a state of being skewed to the radius direction directed to the permanent magnet, the other pattern is formed by patterning the other pattern such that respective electrically independent single pieces of the wirings are aligned at constant intervals to the radius direction in a state of being orthogonal to the radius direction directed to the permanent magnet, and in the bonding step, both ends of the respective wirings of the other pattern are respectively electrically connected to one ends and other ends of contiguous wirings of the wirings of the one pattern to thereby function as the coil.

According to the stator and the method of fabricating the stator of the invention, when the coil pattern and the conductive pattern are formed by the base board working step and the base member working step, either of the patterns is formed by patterning the electrically independent single piece of the wirings are aligned at the constant intervals to the radius direction directed to the permanent magnet. At this occasion, the one pattern is patterned in a state of making the plurality of wirings skewed to the radius direction.

Further, the other pattern is formed by being patterned such that the electrically independent single pieces of the wirings are aligned at the constant intervals in the radius direction directed to the permanent magnet. At this occasion, different from the case of the above-described one pattern, the other pattern is patterned in the state of making the plurality of wirings orthogonal to the radius direction.

The coil pattern and the conductive pattern are respectively patterned as described above, and therefore, when the cover is fitted to cover the tooth, the both ends of the respective wirings of the other pattern (for example, conductive pattern) are brought into a state of being respectively brought into contact with the one ends and the other ends of the contiguous wirings in the wirings of the one pattern (for example, coil pattern). Therefore, in the bonding step, by electrically connecting the wiring of the coil pattern and the wiring of the conductive pattern, the surrounding of the tooth can be wound spirally to be able to function as the coil firmly.

Further, according to the stator of the invention, there is provided the stator of the invention, further comprising an insulating flexible board including a board main body formed with a through hole having a diameter substantially the same as an inner diameter of the ring-like portion, rings formed to be laminated to front end portions of the plurality of teeth, and a plurality of connecting portions both ends of which is connected to the board main body and the rings and which are formed to be laminated to the plurality of teeth for interposing the stator core between the flexible board and the base board, wherein the cover is fixed to the connecting portion.

Further, according to the method of fabricating the stator according to the invention, there is provided the method of fabricating the stator of the invention, further comprising a cover fixing step of preparing an insulating flexible board including a board main body formed with a through hole having a diameter substantially the same as an inner diameter of the ring-like portion, rings formed to be laminated to front end portions of the plurality of teeth, and a plurality of connecting portions both ends of which are connected to the board main body and the rings and which are formed to be laminated to the plurality of teeth, and fixing the cover to the connecting portion, wherein in the bonding step, the cover is bonded to the base board in a state of laminating the flexible board to the stator core such that the stator core is interposed between the flexible board and the base board.

According to the stator and the method of fabricating the stator of the invention, after forming the plurality of covers by the base member working step, there is carried out the cover fixing step of fixing the plurality of covers to the insulating flexible board constituted by the base main body and the ring and the connecting portion.

After the cover fixing step, the flexible board is laminated to the stator core such that the stator core is interposed between the flexible board and the base board. At this occasion, the respective connecting portions of the flexible board are fixed to the covers, and therefore, the plurality of covers can efficiently and successively be fitted to the plurality of teeth. That is, it is not necessary to fit the respective covers thereto one by one, and therefore, the covers can further efficiently be fitted thereto and the base board and the covers can be bonded in a short period of time. Therefore, the stator is facilitated to fabricate and a fabricating time period can be shortened.

Further, the board main body of the flexible board is formed with the through hole having the inner diameter substantially the same as that of the ring-like portion of the stator core, and therefore, when the flexible board and the stator core are laminated, the ring-like portion and the board main body are brought into the laminated state. Similarly, also with regard to the ring and the connecting portion, when the flexible board and the stator core are laminated, the ring and the connecting portion are brought into a state of being respectively laminated to the front end portion and the tooth. Therefore, the stator core can be interposed between the flexible board and the base board to be fixed thereby, and the plurality of teeth and the front end portions can integrally and solidly be connected by way of the flexible board and the base board. Therefore, the respective teeth can further firmly be prevented from being vibrated by being influenced by rotation of the permanent magnet.

Further, according to the stator of the invention, there is provided the stator of the invention, further comprising an insulating flexible board including a board main body formed with a through hole having a diameter substantially the same as an inner diameter of the ring-like portion, rings formed to be laminated to front end portions of the plurality of teeth, and a plurality of connecting portions both ends of which are connected to the board main body and the rings and which are formed to be laminated to the plurality of teeth for interposing the stator core between the flexible board and the base board, wherein the cover is integrally formed with the connecting portion.

Further, according to the method of fabricating the stator of the invention, there is provided the method of fabricating the stator of the invention, wherein in the base member working step, after forming a flexible board having a board main body formed with a through hole having a diameter substantially the same as an inner diameter of the ring-like portion, rings formed to be laminated to the front end portions of the plurality of teeth and a plurality of connecting portions both ends of which are connected to the board main body and the rings and which are formed to be laminated to the plurality of teeth from the insulating base member, the conductive pattern is patterned to the connecting portion and carrying out the folding forming to thereby integrally form the connecting portion and the covers, in the bonding step, the cover is bonded to the base board in a state of laminating the flexible board to the stator core such that the stator core is interposed between the flexible board and the base board.

According to the stator and the method of fabricating the stator of the invention, when the base member working step is carried out, first, the flexible board constituted by the board main body and the ring and the connecting portion is formed from the insulating base member. Successively, the conductive patterns are patterned to the connecting portions formed to overlap the plurality of teeth, thereafter, folded to form. Thereby, the connecting portion and the cover can integrally be formed.

Further, in the bonding step, the flexible board is laminated to the stator core such that the stator core is interposed between the flexible board and the base board. At this occasion, the respective connecting portions of the flexible board are integrally formed with the covers, and therefore, the plurality of covers can efficiently and successively be fitted to the plurality of teeth. That is, it is not necessary to fit the respective covers thereto one by one, and therefore, the covers can be fitted thereto further efficiently and the base board and the covers can be bonded in a short period of time. Therefore, the stator is facilitated to fabricate and the fabrication time period can be shortened.

Further, the board main body of the flexible board is formed with the through hole having the inner diameter substantially the same as that of the ring-like portion of the stator core, and therefore, when the flexible board and the stator core are laminated, the ring-like portion and the board main body are brought into a laminated state. Similarly, also with regard to the ring and the connecting portion, when the flexible board and the stator core are laminated, the ring and the connecting portion are respectively brought into a state of being laminated to the front end portion and the tooth. Therefore, the stator core can be interposed between the flexible board and the base board to be fixed thereby, and the plurality of teeth and the front end portions can integrally and solidly be connected by way of the flexible board and the base board. Therefore, it can further firmly be prevented that the respective teeth are vibrated by being influenced by rotation of the permanent magnet.

Particularly, the flexible board and the cover are integrally formed from one sheet of the insulating base member, and therefore, a positional shift between the connecting portion and the cover is not brought about and the covers can further highly accurately be coated to the teeth. Further, the fabrication time period can further be shortened.

Further, according to the stator of the invention, there is provided the stator of the invention, wherein the teeth are formed by a number of a multiple of 3 and the flexible board is constituted by 3 sheets of boards comprising a first flexible board, a second flexible board and a third flexible board, the first flexible board includes the connecting portions laminated to the teeth by being spaced apart from each other by every 2 thereof in the plurality of teeth, the second flexible board includes the connecting portions laminated to the teeth at positions phases of which are shifted from phases of the teeth laminated to the connecting portion of the first flexible board by one phase in the plurality of teeth, and the third flexible board includes the connecting portions to be laminated to the teeth at positions phases of which are shifted from the teeth laminated to the connecting portions of the second flexible board by one phase in the plurality of teeth.

Further, according to the method of fabricating the stator of the invention, there is provided the method of fabricating the stator of the invention, wherein in the stator core forming step, the teeth are formed by a number of a multiple of 3, in the cover fixing step, as the flexible board, there are prepared 3 sheets of boards comprising a first flexible board having the connecting portions laminated to the teeth by being spaced apart from each other by every 2 thereof in the plurality of teeth, a second flexible board having the connecting portions laminated to the teeth at positions phases of which are shifted from the teeth laminated to the connecting portions of the first flexible board by one thereof in the plurality of teeth, and a third flexible board having the connecting portions laminated to the teeth at positions phases of which are shifted from the teeth laminated to the connecting portions of the second flexible board by one thereof in the plurality of teeth and the covers are fixed to the connecting portions of the respective flexible boards, and in the bonding step, after laminating the flexible boards to the stator core successively from the first flexible board, the cover is bonded to the base board.

According to the stator and the method of fabricating the stator of the invention, in the stator core forming step, the stator core is formed such that the number of the teeth is constituted by the number of the multiple of 3, for example, 18 slots. Successively, in the cover fixing step, as the flexible board, 3 sheets of the flexible boards, that is, the first flexible board, the second flexible board and the third flexible board are prepared. In this case, the intervals of the connecting portions of the first flexible board are adjusted to be laminated to the teeth by being spaced apart from each other by two thereof. Further, the intervals of the connecting portions of the second flexible board are adjusted to be laminated to the teeth at the positions the phases of which are shifted from the teeth laminated with the connecting portions of the first flexible board by 1 slot. Further, the intervals of the connecting portions of the third flexible board are adjusted to be laminated to the teeth at the positions the phases of which are shifted from the teeth laminated with the connecting portions of the second flexible board by 1 slot. Thereby, when 3 sheets of the flexible boards and the stator core are laminated, the connecting portions of the respective flexible boards are not laminated to the connecting portions of other flexible boards.

Further, after fixing the covers to the connecting portions of the respective flexible boards, the covers are fitted to the teeth while laminating the flexible boards to the stator core successively from the first flexible board. Further, finally, the covers are fitted to the base board. At this occasion, as described above, the connecting portions of the respective flexible boards are not laminated to the connecting portions of other flexible boards, and therefore, the covers fixed to the respective connecting portions can firmly be fitted to the teeth.

Particularly, the flexible boards are constituted by 3 sheets thereof, the covers fixed to the connecting portions of the respective flexible boards are alternately fitted to the teeth, and therefore, the permanent magnet can be rotated by supplying the 3 phase alternating currents. That is, the three phase alternating currents can be supplied in a state in which the conductive pattern of the cover fixed to the first flexible board is used exclusive for U phase, the conductive pattern of the cover fixed to the second flexible board is used exclusive for V phase, the conductive pattern of the connecting portion fixed to the third flexible board is used exclusive for W phase.

In this way, the respective flexible boards can be made to constitute the boards respectively exclusively used for U phase, V phase, W phase, and therefore, leading of wirings to respective flexible boards is further facilitated.

Further, according to the method of fabricating the stator of the invention, there is provided the method of fabricating the stator of the invention, in the stator core forming step, the teeth are formed by a number of a multiple of 3, in the press member working step, as the flexible board, there are prepared 3 sheets of boards comprising a first flexible board having the connecting portions laminated to the teeth by being spaced apart from each other by every 2 thereof in the plurality of teeth, a second flexible board having the connecting portions laminated to the teeth at positions phases of which are shifted from the teeth laminated to the connecting portions of the first flexible board by one thereof in the plurality of teeth, and a third flexible board having the connecting portion laminated to the teeth at positions phases of which are shifted from the teeth laminated to the connecting portions of the second flexible board by one thereof and the connecting portions and the covers of the respective flexible boards are integrally formed, and in the bonding step, after laminating the flexible boards to the stator core successively from the first flexible board, the cover is bonded to the base board.

According to the method of fabricating the stator of the invention, in the stator core forming step, the stator core is formed such that the number of the teeth is constituted by the number of the multiple of 3, for example, 18 slots. Successively, in the base member working step, as the flexible board, 3 sheets of the boards, that is, the first flexible board, the second flexible board and the third flexible board are respectively formed. At this occasion, the intervals of the connecting portions of the first flexible board are adjusted to be laminated to the teeth to be spaced apart from each other by two thereof. Further, the intervals of the connecting portions of the second flexible board are adjusted to be laminated to the teeth at the positions the phases of which are shifted from the teeth laminated with the connecting portions of the first flexible board by 1 slot. Further, the intervals of the connecting portions of the third flexible board are adjusted to be laminated to the teeth at the positions the phases of which are shifted from those of the teeth laminated with the connecting portion of the second flexible board by 1 slot. Thereby, when 3 sheets of the flexible boards and the stator core are laminated, the connecting portions of the respective flexible boards are not laminated to the connecting portions of other flexible boards.

Thereby, 3 sheets of the flexible boards integrally formed with the covers at the connecting portions can be provided. Further, in the bonding step, the cover is fitted to the tooth while laminating the flexible boards to the stator core successively from the first flexible board. Further, finally, the cover is bonded to the base board. At this occasion, as described above, the connecting portions of the respective flexible boards are not laminated to the connecting portions of other flexible board, and therefore, the covers constantly formed at the respective connecting portions can firmly be fitted to the teeth.

Particularly, the flexible boards are constituted by 3 sheets thereof, the covers constantly formed at the connecting portions of the respective flexible boards are alternately fitted to the teeth, and therefore, the permanent magnet can be rotated by supplying three phase alternating currents. That is, three phase alternating currents can be supplied in a state in which the conductive pattern of the cover integrally formed to the first flexible board is used exclusive for U phase, the conductive pattern of the cover integrally formed to the second flexible board is used exclusive for V phase, the conductive pattern of the connecting portion integrally formed to the third flexible board is used exclusive for W phase.

In this way, the respective flexible boards can be made to constitute the boards used exclusive for U phase, V phase, W phase, and therefore, leading of wirings to the respective flexible boards or the like is further facilitated.

Further, according to the stator of the invention, there is provided the stator of the invention, wherein the other face of the base board is formed with connection wirings for electrically connecting predetermined coil patterns in the plurality of coil patterns.

Further, according to the method of fabricating the stator of the invention, there is provided the method of fabricating the stator of the invention, wherein in the base board forming step, connection wirings for electrically connecting predetermined coil patterns of the plurality of coil patterns are formed on the other face of the base board.

According to the stator and the method of fabricating the stator of the invention, by the connection wiring formed on other face of the base board (face on a side opposed to one face formed with the coil pattern), predetermined coil patterns of the plurality of coil patterns can electrically be connected. Thereby, the coil patterns can properly be used and an easiness of use can be promoted. For example, the coil patterns can be made to function as U phase, V phase, W phase in order to deal with three phase alternating currents.

Further, according to the stator of the invention, there is provided the stator of the invention, a dummy pattern having a layer thickness substantially the same as a layer thickness of the connection wiring is formed on the other face of the base board over substantially an entire face thereof to fill spaces among the connection wirings.

Further, according to the method of fabricating the stator of the invention, there is provided the method of fabricating the stator of the invention, wherein in the base board forming step, a dummy pattern having a layer thickness substantially the same as a layer thickness of the connection wiring is formed over an entire face of the other face to fill spaces among the connection wiring.

According to the stator and the method of fabricating the stator of the invention, the dummy pattern having the layer thickness substantially the same as that of the connection wiring disposed is formed to fill the spaces among the connection wirings over substantially an entire face of other face of the base board, and therefore, a variation in the thickness of the base board can be eliminated. That is, a stepped difference by the thickness of the connection wiring can be eliminated. Further, the dummy pattern is formed to fill the spaces among the connection wirings, and therefore when the base board is mounted, the connection wiring or the dummy pattern is necessarily present on the back side of the range of laminating the coil pattern and the conductive pattern of the cover.

Therefore, even when jointing is carried out by a simple method of pressing the cover to the base board, a press force can firmly be transmitted to the cover, and the cover can be pressed uniformly. As a result, the conductive pattern and the coil pattern can firmly be bonded and high quality formation can be achieved by further promoting high reliability of the bonding.

Further, a motor according to the invention comprises a stator according to any one of the invention, and a shaft member rotatably supported around the axis line in a state of holding the permanent magnet.

According to the motor of the invention, the thinned stator is provided, and therefore, thinned formation of the motor per se can be achieved. Further, the stator is also the stator excellent in efficiency of the electromotive force and heat radiating performance and formed by high function, and therefore, power consumption can be restrained and high quality formation can be achieved. Further, since the stator promoting durability is provided, durability of the motor per se can be promoted.

Further, a record medium drive apparatus according to the invention comprises the motor of the invention, a holding portion provided at a shaft member for holding a record medium capable of recording various information, and a bearing for rotatably supporting the shaft member around the axis line.

According to the record medium drive apparatus of the invention, the thinned motor is provided, and therefore, thinned formation of the apparatus per se can be achieved. Further, the motor is also the motor excellent in the efficiency of the electromotive force and the heat radiating performance and formed by the high function, and therefore, power consumption can be restrained and high quality formation can be achieved. Further, since the motor promoting the durability is provided, the durability of the apparatus per se can be promoted.

According to the stator and the method of fabricating the stator of the invention, the thinned formation and the high function formation can be achieved, the efficiency of the electromotive force and the heat radiating performance can be promoted, further, the durability can be promoted by eliminating unnecessary vibration. Particularly, the coil can be provided easily and in a short period of time without using the coiling machine, and therefore, low cost formation can be achieved by promoting a fabrication efficiency.

Further, according to the motor and the record medium drive apparatus of the invention, the thinned formation can be achieved, the power consumption can be restrained and the quality can be promoted. Further, durability can be promoted.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

An explanation will be, given of a first embodiment of a stator, a motor and a record medium drive apparatus as well as a method of fabricating a stator according to the invention in reference toFIG. 1throughFIG. 13as follows.

As shown byFIG. 1, a record medium drive apparatus1of the embodiment includes a spindle motor (motor)2for driving to rotate a hard disk (record medium) D capable of recording various information around an axis line L, a fitting portion (holding portion)4cprovided at a hub (shaft member)4of the spindle motor2for fitting to hold the hard disk D, and a hydraulic dynamic bearing (bearing)3for rotatably supporting the hub4around the axis line L.

The spindle motor2is a motor of an inner rotor type and includes the hub4rotatably supported around the axis line L, a permanent magnet5in a ring-like shape held by the hub4, and a stator6opposedly arranged to surround a surrounding of the permanent magnet5.

The hub4includes a shaft portion4aformed substantially in a circular column shape centering on the axis line L, and a flange4bformed to extend outward in a radius direction from an outer peripheral face of the shaft portion4aand formed to interpose a flange3bof a sleeve3amentioned later from upper and lower sides. Further, an upper end of the hub4is inserted into a center hole of the hard disk D to constitute the fitting portion4cfor fitting and holding the hard disk D. Further, the permanent magnet5is formed such that a sectional area along the radius direction becomes rectangular, and the outer peripheral face thereof becomes a face in a parallel with the axis line L. The permanent magnet5is held by the flange4b.

The hydraulic dynamic bearing3is formed by a cup-like shape and includes a sleeve3aa base end side of which is fixed by a base7, and oil W supplied to between the sleeve3aand the hub4. The sleeve3aconstitutes a containing portion an inner side of which is formed by a circular shape in a section thereof and which contains the shaft portion4a. Further, an upper end of the sleeve3ais formed with the flange3bformed to extend to an outer side in a radius direction. Further, it is designed to form a small gap between the sleeve3aand the hub4and the oil W is supplied to the gap. Further, the oil W is prevented from leaking to a side of the permanent magnet5by a seal, not illustrated.

Further, upper and lower outer surfaces of the flange3bopposed to the flange4bare formed with pluralities of thrust dynamic pressure generating grooves, not illustrated, referred to as herringbone grooves. Further, also an outer surface of the shaft portion4aopposed to an outer peripheral face of the sleeve3ais similarly formed with a plurality of radial dynamic pressure generating grooves referred to as herringbone grooves, not illustrated. Thereby, when the hub4is rotated, the oil W flows along the thrust dynamic pressure generating groove and the radial dynamic pressure generating groove to increase, a pressure to thereby stably rotate the hub4.

That is, the thrust dynamic pressure generating groove and the radial dynamic pressure generating groove are portions constituting the hydraulic dynamic bearing3.

As shown byFIG. 2throughFIG. 4, the stator6is constituted by combining a base board10, a stator core11, and a cover12, and is fixed in a state of being mounted on the base7as shown byFIG. 1.

The base board10is an insulating printed board and is formed with a through hole10ainserted with the permanent magnet5at a center thereof as shown byFIG. 5. Further, the base board10of the embodiment is provided with a projected portion10bformed with outside connection terminals15a,15b,15c,15d, mentioned later, in a state of being projected to outside from a portion of an outer periphery. Further, coil patterns13are formed on a surface (one face) of the base board10in a peripheral direction surrounding the through hole10aat respective predetermined angles centering on the axis line L. According to the embodiment, an example is taken by a case of forming 18 pieces of the coil patterns13at respective 20 degrees around the axis line L.

As shown byFIG. 6, the coil pattern13is patterned by a conductive material of copper or the like such that single pieces of wirings13aelectrically independent from each other are aligned at constant intervals in the radius direction in a state of being skewed to the radius direction directed to the permanent magnet5. That is, the respective wirings13aare patterned to shift a pitch by one stage at both ends.

Further, according to the respective coil patterns13, portions of the wirings13aare electrically connected to connection wirings14and the respective coil patterns13are connected to each other at every 2 thereof by the connection wirings14. Specifically speaking, as shown byFIG. 5, FIG.7andFIG. 8, the connection wirings14for connecting every 2 of the coil pattern13are pertinently patterned on a surface and a rear face (other face) of the base board10. Further, the connection wirings14are electrically connected between the surface side and the rear face side of the base board10by way of a through hole (an inner face of which is plated with a conductive material), not illustrated, penetrating the base board10. Further, the connection wirings14are connected to 4 of the outside connection terminals15a,15b,15c,15dformed at a projected portion10bof the base board10. Further, among 4 of the outside connection terminals15a,15b,15c,15d, the one outside connection terminal15ais a common ground terminal and remaining three of the outside connection terminals15b,15c,15dare connected to a three phase alternating current power source as connection terminals for U phase, V phase, W phase.

As shown byFIG. 1, the base board10constituted in this way is fixed in a state of being mounted to the base7. Further, the connection wiring14patterned to the rear face of the base board10is coated by an insulating layer, not illustrated. Thereby, the connection wiring14and the base7are not conducted to each other.

The stator core11is formed by punching a flat plate of a magnetic member of a silicon steel plate or the like by a press or the like and as shown, byFIG. 4, the stator core11includes a core back (ring-like portion)11aformed in a ring-like shape centering on the axis line L, teeth11bbase ends of which are fixed to the core back11aand which are formed to extend in a radius direction directed to the permanent magnet5, and formed by 18 pieces thereof constituting a number the same as the number of the coil patterns13at respective predetermined angles (20 degrees) (that is, the slot number is 18 slots) and front end portions11crespectively formed at front ends of the plurality of teeth11band opposed to an outer peripheral face (peripheral face) of the permanent magnet5.

Further, when the stator core11is formed, the stator core11may be formed by laminating punched magnetic members (for example, 2 layers). Further, an outer surface of the stator core11is coated with an insulating layer, not illustrated, (coated layer).

As shown byFIG. 9, the stator core11constituted in this way is laminated onto the base board10in a state in which the teeth11bare opposed to the coil patterns13patterned onto the base board10. In this case, the stator core11is laminated in a state of bringing all of the core back11a, the teeth11band the front end portions11cinto press contact with the base board10.

As shown byFIG. 10andFIG. 11, the covers12are constituted by base members15fitted to the base board10in a state of being respectively fitted to the teeth11blaminated onto the base board10and covering surroundings of the teeth11b, and conductive patterns16patterned to inner faces of the base members15and electrically connected to the coil patterns13.

The base member15is an insulating sheet of polyimide or the like and is pressed by die or the like in consideration of a sectional shape (width, thickness) of the teeth11bas shown byFIG. 12. Thereby, the base member15can be fitted to the tooth11bto cover to fit together.

Further, as shown byFIG. 13, the conductive pattern16is patterned by a conductive material of copper or the like at an inner face of the base member15such that single pieces of the wirings16aindependent from each other electrically are aligned at constant intervals in the radius direction directed to the permanent magnet5. Further, at this occasion, the respective wirings16aare patterned to be orthogonal to the radius direction.

Thereby, the respective wirings16aof the conductive pattern16are brought into a state in which when the cover12is fitted to the tooth11b, respective both ends thereof are brought into contact with one end P1and other ends P2of the wirings13acontiguous to each other in the wirings13aof the coil pattern13as shown byFIG. 6.

Therefore, the coil pattern13and the conductive pattern16function as a coil of exciting the tooth11bby spirally winding the surrounding of the tooth11bby being connected to each other electrically.

Next, a method of fabricating the stator6will be explained as follows.

The fabricating method according to the embodiment is a fabricating method by pertinently carrying out a base board working step, a stator core forming step, a layer coating step, a base member working step, a fixing step, and a bonding step.

First, as shown inFIG. 5throughFIG. 9, there is carried out a base board working step of forming the through hole10aat the base board10and patterning 18 pieces of the coil patterns13at respective 20 degrees centering on the axis line L in a peripheral direction surrounding the through hole10a. Further, at this occasion, 4 of the outside connection terminals15a,15b,15c,15dare formed on the projected portion10bof the base board10, and the connection windings14are patterned on the surface and the rear face of the base board10. Specifically, layers of a conductive material are formed on the two faces of the base board10formed with the through hole, thereafter, by utilizing a photolithography technology, the outside connection terminals15a,15b,15c,15d, the coil patterns13and the connection windings14are patterned in one motion.

As a result, the base board10shown inFIG. 4can be provided. Further, an insulating layer is coated on the connection wiring14patterned on the rear face of the base board10.

Further, there is carried out the stator core forming step of forming the stator core11at a timing the same as that of the above-described base board working step, or a timing therebefore or thereafter. That is, the stator core11comprising the core back11aand the teeth11band the front end portions11cis formed by punching a flat plate of a magnetic member by a press or the like. At this occasion, the teeth11bare formed by a number the same as that of the coil patterns13, that is, 18 pieces by angles the same as angles of forming the coil patterns13. Thereby, the stator core11shown inFIG. 4can be provided. Further, there is carried out a layer coating step of coating an insulating layer on an outer surface of the stator11by a shape of a thin layer.

Further, there is carried but the base member working step of forming the cover12by a timing the same as those of the respective steps, or a timing therebefore or thereafter. That is, the conductive pattern16is formed by patterning a conductive material on the base member15of polyimide or the like, thereafter, as shown byFIG. 12, the base member15is folded to form by utilizing a die in a state of making the conductive pattern16disposed on an inner side to thereby form the cover12. In this case, the cover12is formed in consideration of the sectional shape (width, thickness) of the tooth11bsuch that the cover12can be fitted to the tooth11bto cover to fit together. Further, the covers12are formed by 18 pieces constituting the number of the teeth11b. After finishing the above-described respective steps, first, there is carried out the fixing step of fixing the base board10and the stator core11. That is, the base board10and the stator core11are laminated together such that the coil patterns13and the teeth11bare respectively opposed to each other, thereafter, the both members are fixed by adhering or the like. As shown byFIG. 9, there is brought about a state in which the respective teeth11bare mounted on the coil pattern13. Further, the stator core11is brought into a state of being laminated together with the base board10in a state of bringing all of the core back11a, the teeth11band the front end portions11cinto face contact with the base board10. After finishing the fixing step, as shown byFIG. 10, the covers12are respectively fitted to the teeth11blaminated on the base board1Q, that is, fitted to cover the teeth11b. At this occasion, as shown byFIG. 11, the conductive pattern16pattered on an inner face of the cover12is brought into a state of being brought into contact with the tooth11b. Further, the both ends of the respective wirings16aof the conductive patterns16are respectively brought into contact with the one ends P1and the other ends P2of the wirings13acontiguous to each other in the wirings13aof the coil pattern13.

Further, the conductive pattern16and the coil pattern13are electrically connected by bonding the cover12to the baseboard10by soldering, thermal pressure bonding, ultrasonic bonding, welding or the like. By the electric connection, the surrounding of the tooth11bcan spirally be wound by the coil pattern13and the conductive pattern16to be able to function as the coil for exciting the tooth11b.

The stator6shown inFIG. 2andFIG. 3can be fabricated by the above-described.

Next, an operation of the record medium drive apparatus1constituted in this way will be explained as follows.

First, the outside connection terminal15aconstituting the common ground terminal is connected to the ground and the remaining three of the outside connection terminals15b,15c,15dare connected to the three phase alternating current power source, thereafter, the three phase alternating currents are supplied to the respective coil patterns13and the respective conductive patterns16by way of the communication windings14. Then, since the coil patterns13and the conductive patterns16function as the coils (U phase, V phase, W phase) spirally winding the teeth11b, the teeth11bare excited and a magnetic field is generated. By the magnetic field, the hard disk D can be rotated by rotating the permanent magnet5and the hub4around the axis line L.

Further, in this case, the stator core11includes the front end portions11copposed to the outer peripheral face of the permanent magnet5at the front ends of the teeth11b, and therefore, delivery of a magnetic flux between the stator core11and the permanent magnet5become dense. Therefore, the hub4can efficiently be rotated. Further, in accordance with rotation of the hub4, the oil W flows along the thrust dynamic pressure generating groove and the radial dynamic pressure generating groove, and therefore, a pressure is increased. Thereby, the hub4is supported by forces in the thrust direction and the radial direction by the hydraulic dynamic bearing3, and therefore, the hub4is smoothly rotated.

Particularly, the coil pattern13patterned to the base board10and the conductive pattern16patterned to the inner face of the cover12can be made to function as the coil, and therefore, different from the constitution of forming the coil by mechanically winding the coil wire as in the related art, the coiling machine needs not to be used. Therefore, the number of the teeth11b, that is, the slot number can be increased to 18 pieces. Therefore, the turn number of the coil per single tooth11bcan be reduced, and the thickness can be restrained as less as possible. Therefore, the thinned formation of the total can be achieved.

Further, the coil patterns13and the conductive patterns16are brought into the state of being brought into contact with the teeth11bby way of the insulating layer. Therefore, a wasteful gap is not formed between the coil pattern13and the conductive pattern16and the tooth11b. Therefore, after ensuring insulation between the coil pattern13and the conductive pattern16and the tooth11b, lengths of the coil pattern13and the conductive pattern16can be constituted by necessary minimum lengths and an electric resistance can be restrained as less as possible. Therefore, the electromotive force can efficiently be generated without reducing reliability and wasteful power consumption can be eliminated.

Further, the stator core11other than the teeth11bis exposed, and therefore, an exposure area exposed to the atmosphere is larger than that of the related art. Therefore, heat generated by electricity conduction can efficiently be radiated. Therefore, an operational area, exfoliation of a part by heat or the like can be restrained from being brought about and the reliability can be promoted.

Further, it is not necessary to utilize the coiling machine, and therefore, as shown byFIG. 3, the gap T3between the contiguous front end portion11ccan be made to be as small as possible. Therefore, a portion of a magnetic line of force flowing through the tooth11bcan be made to flow to the contiguous tooth11bby way of the front end portion11c, and the magnetic force of attracting the permanent magnet5and the front end portion11cto each other can be reduced. As a result, a cogging torque can be reduced and high function formation can be achieved.

Further, the stator core11is fixed onto the base board10over the core back11a, the teeth11band the front end portions11cand further pressed to the base board10by the covers12. Therefore, although base end sides of the respective teeth11bare fixed to the core back11ain a cantilever state, the respective teeth11bare brought into a state of being connected to each other by way of the base board10. Therefore, vibration of the respective teeth11bcaused by an influence of rotation of the permanent magnet5can be restrained. When the base end sides of the respective teeth11bare only fixed to the core back11aassumedly, there is a concern that unnecessary vibration of fluctuating the respective teeth11bor the like is brought about by being influenced by rotation of the permanent magnet5. However, as descried above, the respective teeth11bare brought into a state of being connected to each other, and therefore, the unnecessary vibration can be restrained as less as possible. Therefore, strange sound can be eliminated and durability can be promoted.

As described above, according to the stator6of the embodiment, thinned formation and high performance formation can be achieved, efficiency of the electromotive force and heat radiation performance can be promoted, further, durability can be promoted by eliminating unnecessary vibration. Particularly, the coil can be provided easily and in a short period time without using the coiling machine, and therefore, low cost formation can be achieved by promoting a fabrication efficiency.

Further, according to the spindle motor2of the embodiment, since the above-described stator6is provided, thinned formation can be achieved. Further, owing to the stator6excellent in efficiency of the electromotive force and brought into high function formation, power consumption can be restrained and high quality formation can be achieved. Further, durability of the spindle motor2per se can be promoted.

Further, according to the record medium drive apparatus1of the embodiment, since the above-descried spindle motor2is provided, thinned formation can be achieved and the quality can be promoted by restraining power consumption. Further, durability can be promoted.

Further, although according to the above-described first embodiment, when the cover12is bonded, the cover12is bonded by soldering, thermal pressure bonding, ultrasonic bonding, welding or the like, when the respective conductive patterns16of the cover12cannot summarizingly be bonded to the coil patterns13, it is preferable to utilize a heater H shown inFIG. 14. According to the heater H, a head portion of a front end thereof is bifurcated to be able to be brought into contact with both ends of the cover12covered onto the tooth11b.

When the bonding is carried out by utilizing the heater H, first, the base board10fixed with the stator core11is mounted onto a horizontal base, not illustrated. Further, after the head reaches a predetermined temperature, the heater H is pressed to the both ends of the cover12as shown byFIG. 14. At this occasion, the heater H is pressed by a predetermined pressure. That is, while heating the cover12, the cover12is pressed to the base board10. As a result, the respective conductive patterns16of the covers12can simultaneously be bonded to the coil patterns13in one motion.

By carrying out the bonding by utilizing the heater H in this way, the conductive pattern16and the coil pattern13can further firmly be connected and further, a time period consumed for the bonding can be shortened, and therefore, the bonding is further preferable.

Meanwhile, as shown byFIG. 8, the rear face of the base board10is pertinently patterned with the connection wiring14. Therefore, when the cover12is fitted to the tooth11b, as shown byFIG. 15, there are necessarily brought about portions at which the connection wirings14are present and portions at which the connection wirings14are not present on a lower side of the cover12. Therefore, there is a case in which a stepped difference is brought about by the thickness of the connection wiring14when the base board10is mounted onto the horizontal base.

Therefore, when the heater H is pressed thereto, with regard to the portion at which the connection wiring14is formed at a rear face of the base board10, a press force is firmly transmitted to the horizontal base by way of the connection wiring14. Therefore, the pressure can firmly be applied to the cover12and the bonding can firmly be carried out. On the other hand, with regard to a portion at which the connection wiring14is not formed at the rear face of the base board10, there is brought about a state in which the base board10is floated above the horizontal base, and there is a concern that the press force cannot firmly be transmitted and the bonding cannot firmly be carried out.

In this way, there is a case in which owing to the stepped difference brought about by presence/absence of the connection wiring14, there are brought about a portion in which the press force is transmitted and a portion in which the press force is difficult to be transmitted and the base board10cannot uniformly be pressed. Therefore, there is a possibility of bringing about a nonuniformity in the bonding.

Hence, in order to avoid the above-described drawback, it is preferable to carry out a countermeasure as follows.

That is, when the connection wiring14is patterned to the rear face of the base board10, it is preferable that the connection wiring14is patterned to be opposed to a range of laminating the conductive pattern16and the coil pattern13as much as possible by interposing the cover12. Thereby, when the heater H is pressed, the base board10can be pressed as uniform as possible, and therefore, the bonding is further ensured and reliability is promoted.

Further, in this case, it is preferable to form the width of the connection wiring14as wide as possible more than the width of the coil pattern13. Thereby, the connection wiring14is easier to be opposed to the range of laminating the conductive pattern16of the cover12and the coil pattern13.

Although as described above, it is preferable to devise the patterning of the connection wiring14, there is a case in which it is difficult to always make the connection wiring14opposed to the range of laminating the conductive pattern16of the cover12and the coil pattern13. Hence, it is further preferable to form a dummy pattern19on the rear face side of the base board10.

The dummy pattern19is constituted by, for example, an insulating layer or a conductive layer, and formed over substantially an entire face of the rear face of the base board10as shown byFIG. 16. In this case, as shown byFIG. 17, the dummy pattern19is formed to fill a vacant space to fill surroundings of the connection wirings14in a state of forming a more or less gap between the pattern19and the connection wirings14. Therefore, even when the dummy pattern19is formed by a conductive layer, there is not a concern of conducting the connection wiring14and the dummy pattern19. Further, the dummy pattern19is formed to constitute a layer thickness substantially the same as that of the connection wiring14.

By forming the dummy pattern19at the rear face of the base board10in this way, as shown byFIG. 18, either of the connection wiring14or the dummy pattern19can be made to be necessarily present on the rear face side of the range of laminating the coil pattern13and the conductive pattern16of the cover12. Further, as shown inFIG. 19throughFIG. 21, both of the connection wiring14and the dummy pattern19are constituted by substantially the same layer thickness, and therefore, when the base board10is mounted onto the horizontal base, there is not a variation in the thickness and a height of an upper face of the base board10becomes a uniform height.

Therefore, when the heater H is pressed to the cover12, the press force is conducted to the horizontal base necessarily by way of the connection wiring14or the dummy pattern19, and therefore, the cover12can uniformly be pressed, as a result, the respective conductive patterns16of the covers12can firmly be bonded to the coil patterns13by the same condition, and high quality formation can be achieved by promoting further the reliability of bonding.

Further, when the dummy pattern19is formed, it is preferable to use a conductive material of a material the same as that of the connection wiring14(for example, copper). As a method of forming the dummy pattern19in this case, first, a layer of a conductive material is formed over an entire rear face of the base board10to form the conductive layer. Further, the conductive layer is patterned by utilizing the photolithography technology and the connection wiring14and the dummy pattern19are simultaneously formed. In this way, the connection wiring14and the dummy pattern19can be formed by one step, and therefore, the operational efficiency can be promoted. Further, the connection wiring14and the dummy pattern19can easily and firmly be constituted by the same layer thickness.

Second Embodiment

Next, a second embodiment of a stator according to the invention will be explained in reference toFIG. 22andFIG. 23. Further, in the second embodiment, portions the same as constituent elements of the first embodiment are attached with the same notations and an explanation thereof will be omitted.

A point by which the second embodiment and the first embodiment differ from each other resides in that although according to the first embodiment, 18 pieces of the covers12are scattered one by one, according to the second embodiment, 18 pieces of the covers12are previously fixed to a flexible board21constituted by 3 sheets of flexible boards22,23,24.

That is, as shown byFIG. 22, the stator20of the embodiment is constituted by the base board10, the stator core11, and the flexible board21fixed with the covers12.

As descried above, the flexible board21is constituted by 3 sheets of the boards, that is, the first flexible board22, the second flexible board23and the third flexible board24, respectives thereof are arranged to be able to be laminated to the stator core11. In this case, according to the embodiment, an explanation will be given such that lamination is carried out by making points P3shown inFIG. 22coincide with each other.

Further, basic constitutions of 3 sheets of the flexible boards21are the same. Therefore, the first flexible board22will be explained in details. Further, according to 18 pieces of the covers12, respective 6 pieces thereof are fixed to 3 sheets of the flexible boards21.

As shown byFIG. 22andFIG. 23, the first flexible board22is constituted by a board main body25, a ring26, a connecting portion27. The board main body25is formed with a through hole25aa diameter of which is substantially the same as an inner diameter of the core back11asubstantially at a center position. Further, the board main body25of the embodiment is formed by a ring-like shape.

Further, inside of the through hole25ais formed with the rings26formed to laminate the front end portions11cof 18 pieces of the teeth11b. The ring26is connected to the board main body25by the connecting portion27both ends of which are respectively connected to the ring26and the board main body25. Further, the board main body25, the ring26and the connecting portion27are formed integrally by a base member having a flexibility (for example, a layer or the like Of polyimide, liquid crystal polymer or the like).

6 of the connecting portions27are formed to laminate the teeth11bby being spaced apart from each other by every 2 thereof in 18 pieces of the teeth11b. Further, the cover12is fixed to a lower face of the connecting portion27′.

Further, the second flexible board23is constructed by a constitution the same as that of the first flexible board22, and therefore, a detailed explanation thereof will be omitted. However, as shown byFIG. 22, when the second flexible board23is laminated to the first flexible board22by making the points P3coincide with each other, positions thereof forming the connecting portions27differ from those of the first flexible board22. That is, the second flexible board23is formed with the connecting portions27to laminate the teeth11bat positions phases of which are shifted from those of the teeth11blaminating the connecting portions27of the first flexible board22by 1 slot in 18 pieces of the teeth11b.

Further, the third flexible board24is constructed by a constitution the same as that of the first flexible board22similar to the second flexible board23, and therefore, a detailed explanation thereof will be omitted. However, positions of forming the connecting portions27of the third flexible board24differ from those of the second flexible board23when the third flexible board24is laminated to the second flexible board23by making the points P3coincide with each other. That is, the third flexible board24is formed with the connecting portions27to be laminated to the teeth11bat positions phases of which are shifted from those of the teeth11blaminated to the connecting portions27of the second flexible boards23by 1 slot in 18 pieces of the teeth11b.

Next, a method of fabricating the stator20of the embodiment will be explained as follows. Further, although the method of fabricating the stator20of the embodiment is constituted by a method basically the same as that of the first embodiment, an explanation will be given centering on a different portion.

First, the base board10is prepared by carrying out the base board working step and the stator core11is prepared by carrying out the stator core forming step and the layer coating step. However, in the step of forming the stator core11the teeth11bare formed by 18 pieces thereof constituting a multiple of 3.

Successively, after forming 18 pieces of the covers12by the base member working step, the cover fixing step is carried out. That is, after preparing the flexible board21comprising the first flexible board22, the second flexible board23and the third flexible board24by working a base member having a flexibility, respective 6 pieces of the covers12are fixed to the respective connecting portions27of 3 sheets of the flexible boards22,23,24.

Successively, after laminating the stator core11successively from the first flexible board22, there is carried out the bonding step of bonding the cover12to the base board10.

First, the first flexible board22is laminated to the stator core11to interpose the stator core11between the first flexible board22and the base board10. At this occasion, the connecting portions27of the first flexible board22are fixed with 6 pieces of the covers12, and therefore, the covers12can be fitted to 6 pieces of the teeth11befficiently and successively. That is, different from the case of the first embodiment, it is not necessary to fit the respective covers12thereto one by one, and therefore, the covers12can be fitted, thereto further efficiently and shortening of time can be achieved.

Further, when the first flexible board22is laminated to the stator core11, there is brought about a state of laminating the core back11aand the board main body25, laminating the front end portion11cand the ring26, and laminating the tooth11band the connecting portion27. That is, the stator core11is brought into a state of being fixed by being interposed between the first flexible board22and the base board10over entire ranges of the core back11a, the teeth11band the front end portions11c.

Successively, the second flexible board23is laminated to the first flexible board22. At this occasion, the connecting portion27of the second flexible board23is shifted from the connecting portion27of the first flexible board22by 1 slot in a phase thereof, and therefore, the connecting portions27are not laminated to each other. Therefore, the cover12fixed to the connecting portion27of the second flexible board23can firmly be fitted to the tooth11b.

Successively, the third flexible board24is laminated to the second flexible board23. Further, the cover12fixed to the connecting portion27of the third flexible board24is similarly fitted to the tooth11b.

Thereby, the covers12can be fitted to all of 18 pieces of the teeth11bof the stator core11. Further, finally, the coil pattern13and the conductive pattern16are electrically connected while bonding all of the covers12to the base board10by soldering or the like. As a result, the stator20can be fabricated.

Further, when the respective flexible boards22,23,24are laminated, only the covers12fixed to the respective flexible boards22,23,24may separately be bonded thereto instead of summarizingly bonding the covers12finally.

Particularly, according to the embodiment, as described above, the covers12can be fitted to the tooth11bin a short period of time, and therefore, the stator is facilitated to fabricate and a fabrication time period can be shortened. Further, 3 sheets of the flexible boards22,23,24of the base board10can be fixed by interposing the stator core11therebetween, and therefore, the respective teeth11band the respective front end portions11ccan integrally and solidly be connected by way of 3 sheets of the flexible boards22,23,24and the base board10. Therefore, it can firmly be prevented that the respective teeth11bare vibrated by being influenced by rotation of the permanent magnet5.

Further, the flexible boards21are constituted by 3 sheets thereof, and therefore, three phase alternating currents can be supplied in a state in which the conductive pattern16of the cover12fixed to the first flexible board22is used exclusively for U phase, the conductive pattern16of the cover12fixed to the second flexible board23is used exclusive for V phase, the conductive pattern16of the cover12fixed to the third flexible board24is used exclusively for W phase. In this way, the respective flexible boards21can respectively be constituted by boards exclusive for U phase, V phase, W phase.

Further, although according to the second embodiment, an example is taken by a case of adopting the flexible boards21constituted by 3 sheets of boards of the first flexible board22, the second flexible board23and the third flexible board24, the invention is not limited to the case. For example, a sheet of the flexible board may be formed with 18 pieces of the connecting portions27and the covers12may be fixed to the connecting portions27. However, by dividing the board into 3 sheets of the flexible boards22,23,24as in the second embodiment, the boards exclusive for U phase, V phase, W phase can be constituted, and therefore, the constitution is further preferable.

Further, the constitution of 3 sheets of the flexible boards22,23,24is preferable in a point described below.

That is, when the number of the teeth11b(slot number) is as large as 18 pieces, or the slot number is intended to be constituted by a larger number, also numbers of the connecting portions27and the covers12are increased in accordance therewith. Therefore, when the number is intended to be dealt with by one sheet of the flexible board, an interval between the contiguous connecting portions27is narrowed, and there is brought about a drawback that the covers12are laminated to each other in a state before folding to form the covers12(developed shape).

In this respect, when the flexible boards are constituted by 3 sheets thereof, the interval between the connecting portions27can be spaced apart from each other, it is not necessary to be concerned with the above-described problem. Thereby, the constitution by 3 sheets of the flexible boards22,23,24is further preferable. Further, the problem becomes significant by an increase in the slot number.

Further, according to the above-described second embodiment, as shown byFIG. 24(in order to facilitate to view the drawing, the drawing is illustrated in a state of constituting the conductive pattern16and the connection wiring14by bold lines), the connection wirings14for supplying currents respectively to the coil pattern13and the conductive pattern16may be provided on the sides of the respective flexible boards22,23,24instead of on the side of the base board10. Even in this case, an effect similar to the above-described operation and effect can be achieved.

Further, in this case, when the connection wiring14is patterned, the connection wiring14can easily be patterned without taking other phase into a consideration. That is, when the connection wirings14of U phase, V phase, W phase are patterned on one sheet of the flexible board, it is necessary to pattern the wirings so as not to be electrically brought into contact with each other, and therefore, there is a concern of complicating the wirings, or laminating the wirings to be disconnected or short circuited. However, the connection wirings14are divided into 3 sheets of the flexible boards22,23,24, and therefore, there is not a possibility of the drawback and the connection wirings14can easily and firmly be patterned for respective phases.

Further, although according to the second embodiment, an explanation has been given by taking an example of the case of fixing the covers12to the connecting portions27of the flexible board22,23,24, the invention is not limited thereto but the flexible boards22,23,24and the covers12may integrally be formed. A specific explanation will be given of a method of fabricating the stator20in this case as follows.

First, the base board10is prepared by carrying out the base board working step and the stator core11formed with 18 pieces of the teeth11bis prepared by carrying out the stator core forming step and the layer coating step.

Successively, there is prepared the first flexible board22integrally formed with the covers12by the base member working step. Specifically, first, the flexible board22constituted by the board main body25and the ring26and the connecting portion27are formed by an insulating base member. In this case, a size of the connecting portion27is adjusted such that a width of a portion excluding a portion of connecting the board main body25and the ring26becomes a width before folding to form the cover12(width in developed state). That is, a portion of the connecting portion27is made to serve as the base member15of the cover12.

Successively, after patterning the conductive pattern16at the lower face of the connecting portion27, the portion of the connecting portion27made to serve as the base member15is folded to form. As a result, the first flexible board22integrally formed with the connecting portion27and the cover12can be provided. Further, similarly, the second flexible board23and the third flexible board24are prepared.

Further, by carrying out the bonding step similar to the second embodiment, the stator20including 3 sheets of the flexible boards22,23,24integrally formed with the covers12and the connecting portions27can be fabricated. Even in the case of the fabricating method, operation and effect similar to those of the second embodiment can be achieved.

In addition thereto, according to the fabricating method, it is not necessary to fix the cover12at a later stage, and therefore, there is not brought about a positional shift between the connecting portion27and the cover12. Therefore, the cover12can highly accurately be fitted to the tooth11b, and higher quality formation can be achieved. Further, the cover fixing step can be omitted, and therefore, the fabrication time period can be shortened and the fabrication can further efficiently be carried out.

Further, the technical range of the invention is not limited to the above-described embodiments but can variously be modified within the range not deviated from the gist of the invention.

For example, although an explanation has been given by taking an example of the stator core11formed with 18 pieces of the teeth11bin the above-described embodiments, the number of the teeth11bis not limited to that of the case. Further, although the hub4is rotatably supported by the hydraulic dynamic pressure bearing3, the bearing can also be constituted by a bearing for simply rotatably supporting the hub4without utilizing the dynamic pressure.

Further, although according to the respective embodiments, an example is taken by the case of combining the coil pattern13patterning the wiring13askewedly to the radius direction directed to the permanent magnet5and the conductive pattern16patterning the wiring16ato be orthogonal to the radius direction directed to the permanent magnet5, the invention is not limited to the case but the pattern shape may be reversed. That is, the conductive pattern16patterning the wiring16askewedly to the radius direction directed to the permanent magnet5and the coil pattern13patterning the wiring13aorthogonally to the radius direction directed to the permanent magnet5may be combined.

However, the respective wiring patterns of the coil pattern13and the conductive pattern16may freely be designed without being limited to the above-described patterns so far as when the coil pattern13and the conductive pattern16are combined, the patterns can spirally be wound around the surrounding of the tooth11b.

Further, although according to the respective embodiments, an explanation has been given by constituting the spindle motor2as an inner rotor type, the invention is not limited to the case but the spindle motor2may be constituted by an outer rotor type. Here, an embodiment when the spindle motor2of the first embodiment is constituted by the outer rotor type will simply be explained in reference to the drawings.

As shown byFIG. 25, the record medium drive apparatus30in this case includes the permanent magnet5arranged to surround the surrounding of the stator6, and the stator6arranged opposedly to the permanent magnet5on an inner side of the permanent magnet5, and is constituted such that the permanent magnet5is rotated around the axis line L on the outer side of the stator6.

The permanent magnet5is held by the flange4bof the hub41extended to the outer side of the stator6by exceeding the stator6. Further, other constitution of the hub4and the constitution of the fluid dynamic pressure bearing3are similar to those of the first embodiment.

The stator6is constituted by combining the base board10, the stator core11, and the cover12similar to the first embodiment, and is fixed in a state of being mounted on the base7. However, as shown byFIG. 26, the base board10of the embodiment is formed with the through hole10ato be inserted with the sleeve3aat a center thereof. Thereby, as shown byFIG. 25, the stator6is arranged on the inner side of the permanent magnet5to surround the surrounding of the sleeve3a.

Further, inFIG. 26, illustration of the connection wiring14formed on the base board10is partially omitted.

As shown byFIG. 26, the stator core11is formed such that the tooth11bfixed to the core back11ais extended to an outer side in the radius direction, and the front end of the tooth11bconstitutes the front end portion11copposed to the inner peripheral face (peripheral face) of the permanent magnet5. Further, according to the embodiment, the example is taken by the case of forming 9 pieces (9 slots) of the teeth11bat respective 40 degrees centering on the axis line L. Further, the constitution of the cover12is similar to that of the first embodiment.

The record medium drive apparatus30having the stator6constituted in this way differs in that the permanent magnet5is rotated on the outer side of the stator6and operation and effect similar to those of the first embodiment can be achieved with regard to the other point. Particularly, the flange4bof the hub4can be formed to be long, and therefore, the hard disk D can further stably be held to achieve promotion of stability of rotation and reduction in vibration.

Further, although an explanation has been given by taking the example by the case of applying the spindle motor2of the first embodiment to the outer rotor type, even the spindle motor2of the other embodiment is applicable to the outer rotor type.