Disk drive spindle motor with wiring substrate having extension portion passing through opening in base

A spindle motor includes a stationary unit, a rotary unit and a bearing mechanism. The stationary unit includes a base member, a stator including a plurality of coils and a wiring substrate electrically connected to the stator. The base member includes a tubular portion, a first accommodation portion, an opening portion, a plurality of coil accommodation portions, a second accommodation portion, and at least one through-hole. The wiring substrate includes an arc portion and an extension portion. A lead wire is led out from at least one of the coils and is connected to the arc portion by soldering within the through-hole.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a spindle motor and a disk drive apparatus.

2. Description of the Related Art

Conventionally, a disk drive apparatus such as a hard disk drive apparatus or the like is equipped with a spindle motor for rotating a disk. The disk drive apparatus includes a disk, a housing, a stator, a FPC (Flexible Printed Circuit), and so forth. The housing includes a cover member, a base member, and so forth.

In recent years, the disk drive apparatus is required to become smaller in height and size. Particularly, in order to reduce the height of a 2.5-type disk drive apparatus having a thickness of 7 mm or less, which is used in small-size disk drive apparatuses, it is necessary to reduce the thickness of a housing or a motor arranged within the housing. In general, the motor includes a hub, a coil, a stator core, a wiring substrate, a base member, etc. When assembling the motor, these components are arranged to axially overlap with one another. For the sake of reducing the thickness of the motor, these components need to be made thin. However, if an attempt is made to reduce the overall height of the motor by reducing the turn number of the coils or the lamination thickness of the stator core, the magnetic fluxes generated in the stator during the operation of the motor will be reduced. In other words, the torque constant will be reduced. It is therefore impossible to obtain the torque required in rotating the disk attached to the hub.

In order to reduce the height of the motor, it is therefore necessary to pay attention to, among the components of the motor, the base member that has a large impact on the total axial dimension of the motor. However, if the base member is merely made thin, the rigidity of the base member will be reduced to a great extent. As a result, if a shock is applied from the outside to the base member, it is likely that the base member will be broken and that the disk arranged within the housing will be damaged.

Accordingly, a demand has existed for a structure capable of increasing the rigidity of the base member while reducing the overall height of the motor.

SUMMARY OF THE INVENTION

A spindle motor according to a preferred embodiment of the present invention includes a stationary unit, a rotary unit, and a bearing mechanism. The stationary unit includes a base member, a stator including a plurality of coils, and a wiring substrate electrically connected to the stator.

The base member includes a cylindrical tubular portion, a substantially annular first accommodation portion, an opening portion, a plurality of coil accommodation portions, a second accommodation portion, and at least one through-hole. The tubular portion extends axially about a center axis. The first accommodation portion is arranged on an upper surface of the base member and is depressed toward a lower surface of the base member so as to accommodate at least a portion of the stator. The opening portion is arranged in the first accommodation portion to extend through the base member. The coil accommodation portions are positioned in the first accommodation portion and are arranged around the tubular portion in a circumferential direction. The second accommodation portion is positioned in the first accommodation portion to extend in the circumferential direction and arranged to accommodate a portion of the wiring substrate. At least one through-hole is arranged in the second accommodation portion.

The wiring substrate includes an arc portion arranged in the second accommodation portion and an extension portion arranged on the lower surface of the base member through the opening portion.

A lead wire is led out from at least one of the coils and is connected to the arc portion by soldering within the through-hole.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, the upper side inFIG. 1along a center axis direction of a motor will be just referred to as “upper” and the lower side as “lower”. The up-down direction is not intended to indicate the positional relationship or the orientation when the motor is installed within an actual device. The direction parallel or substantially parallel to the center axis will be referred to as “axial”. The radial direction about the center axis will be just referred to as “radial”. The circumferential direction about the center axis will be just referred to as “circumferential”.

FIG. 1is a sectional view of a spindle motor1according to a preferred embodiment of the present invention. In the following description, the spindle motor1will be just referred to as “motor1”. The motor1is preferably used in a 2.5-type disk drive apparatus having a thickness of about 7 mm or less (e.g., a hard disk drive apparatus), for example. The disk drive apparatus preferably includes a motor1, a housing (not shown), at least one disk (not shown), an access unit (not shown), a connector (not shown), and so forth. The disk is attached to the motor1. The access unit performs at least one of information reading and writing tasks with respect to the disk. The housing preferably includes a base member21and a cover member. The base member21defines a portion of the housing in cooperation with the cover member (not shown).

As shown inFIG. 1, the motor1is preferably of an outer-rotor-type. In the present preferred embodiment, the motor1is preferably a three-phase motor having three phases, namely a U-phase, a V-phase and a W-phase. The motor1preferably includes a stationary unit2as a fixed assembly, a rotary unit3as a rotating assembly, and a fluidic dynamic-pressure bearing mechanism (hereinafter referred to as “bearing mechanism4”). By virtue of the bearing mechanism4, the rotary unit3is rotatably supported with respect to the stationary unit2to rotate about the center axis J1of the motor1.

The stationary unit2preferably includes a base member21, a ring-shaped stator22, and a wiring substrate14. The base member21is a flat member. The base member21preferably includes a tubular portion211and an opening portion24. The tubular portion211has a substantially cylindrical shape. The tubular portion211is arranged substantially at the center of the base member21. The opening portion24axially extends through the base member21. The stator22is arranged around the tubular portion211. The stator22preferably includes a stator core221and coils222. The coils222are arranged in the stator core221. In the stator22, a plurality of (three, in the present preferred embodiment) lead wires2221led out from the U, V and W phase coils are respectively connected to the wiring substrate14by soldering.

One preferred example of the wiring substrate14includes a flexible printed circuit board. The wiring substrate14lies on the upper surface of the base member21and extends from the rotary unit3toward the opening portion24.

The stator core221preferably includes a core-back (not shown) and a plurality of teeth (not shown). The core-back preferably has a ring shape about the center axis J1. The teeth extend radially outward from the outer edge portion of the core-back. Each of the teeth preferably includes a winding portion and a tip end portion. A conductive wire is wound on the winding portion, thereby defining each of the coils222. The tip end portion extends from the outer edge portion of the winding portion in the circumferential opposite directions.

As shown inFIG. 1, the rotary unit3preferably includes a rotor hub31and a rotor magnet321. The rotor hub31preferably includes a hub body311, a cylinder portion312, and a ring-shaped disk placing portion313. The cylinder portion312protrudes downward from the outer edge portion of the hub body311. The disk placing portion313extends radially outward from the lower end of the cylinder portion312. A disk11(shown inFIG. 10) is placed on the disk placing portion313. The rotor magnet321has a ring shape about the center axis J1. The rotor magnet321is arranged inside the cylinder portion312. The disk placing portion313is positioned radially outward of the lower portion of the rotor magnet321. The rotor magnet321is arranged radially outward of the stator22. The rotor magnet321is radially opposed to the stator22. In the motor1, torque is generated between the rotor magnet321and the stator22due to the interaction of the respective magnetic fluxes generated thereby.

As shown inFIG. 1, the bearing mechanism4is preferably a fluidic dynamic-pressure bearing. The bearing mechanism4preferably includes a lubricant, a sleeve41, and a bush42. The sleeve41is a substantially cylindrical member. The sleeve41is preferably defined by sintered metal formed by, for example, baking and solidifying metal powder. The sleeve41has a communication hole411extending through the sleeve41in the up-down direction. The sleeve41is preferably impregnated with a lubricant. The bush42has a substantially cylindrical shape and supports the sleeve41on the inner surface thereof. The stator core221is preferably fixed to the outer surface of the bush42by, for example, press-fitting or caulking. The bush is preferably fixed to the inner surface of the tubular portion211by, for example, press-fitting or the like.

FIG. 2is a perspective view of the base member21, depicting the upper surface side of the base member21.FIG. 3is a perspective view of the base member21, depicting the lower surface side of the base member21. As set forth above, the tubular portion211is arranged in the base member21. A first accommodation portion212is arranged around the tubular portion211. When seen axially, the first accommodation portion212preferably has a substantially annular shape. The first accommodation portion212is a portion arranged on the upper surface of the base member21and depressed toward the lower surface of the base member21. At least a portion of the stator22can be accommodated in the first accommodation portion212. A plurality of coil accommodation portions213is arranged within the first accommodation portion212. The coil accommodation portions213are arranged around the tubular portion211at a regular interval along the circumferential direction. The coil accommodation portions213are not necessarily arranged at a regular interval and may be unevenly arranged. The coil accommodation portions213are portions defined on the upper surface of the base member21and depressed toward the lower surface of the base member21. A second accommodation portion214is arranged inside the first accommodation portion212. The second accommodation portion214is a portion defined on the upper surface of the base member21and depressed toward the lower surface (axial lower side) of the base member21. The second accommodation portion214has a substantially arc-like shape when viewed axially. The second accommodation portion214extends in the circumferential direction along the outer surface of the tubular portion211. A portion of the wiring substrate14can be accommodated within the second accommodation portion214. As shown inFIG. 2, the second accommodation portion214is preferably positioned at the opposite side of the center axis J1from at least one of the coil accommodation portions213.

A third accommodation portion215is preferably arranged within the first accommodation portion212. The third accommodation portion215is a portion depressed toward the lower surface of the base member21. Within the first accommodation portion212, the third accommodation portion215extends radially outward from the second accommodation portion214. The opening portion24axially extending through the base member21is arranged radially outward of the third accommodation portion215.

As shown inFIGS. 1,2, and3, a plurality of through-holes2121is arranged within the second accommodation portion214. The respective through-holes2121axially extend through the base member21. In the present preferred embodiment, three through-holes2121are arranged in the base member21. The through-holes2121are arranged within the second accommodation portion214at a regular interval in the circumferential direction. The respective through-holes2121need not be necessarily arranged at a regular interval. At least one of the coil accommodation portions213is arranged within the second accommodation portion214. The circumferential position of at least one of the through-holes2121is the same as the circumferential position of the third accommodation portion215. In the second accommodation portion214, at least one of the through-holes2121extends through at least one of the coil accommodation portions213. The through-holes2121are provided in plural numbers. The number of the through-holes2121is smaller than the number of the coil accommodation portions213.

A step portion241is arranged in the third accommodation portion215of the opening portion24. As shown inFIG. 3, a groove26is arranged in the end portion of the opening portion24at the side of the lower surface of the base member21. The groove26is axially opposed to the first accommodation portion212. The groove26extends radially outward from the opening portion24. The extension direction of the groove26is parallel or substantially parallel to the extension direction of the third accommodation portion215.

FIG. 4is a plan view of the wiring substrate14. As shown inFIG. 4, the wiring substrate14preferably includes an arc portion141and an extension portion142. When viewed axially, the arc portion141has a substantially arc shape corresponding to the second accommodation portion214. When the motor1is assembled, the arc portion141is arranged within the second accommodation portion214. The thickness of the arc portion141is preferably equal or substantially equal to the axial depth of the second accommodation portion214or smaller than the axial depth of the second accommodation portion214. The extension portion142extends from the arc portion141. The extension portion142preferably includes a power feeding portion143connected to an external power supply or the like. The thickness of the extension portion142is preferably about equal to the axial depth of the third accommodation portion215or smaller than the axial depth of the third accommodation portion215. The thickness of the extension portion142is preferably equal or substantially equal to the axial depth of the groove26or smaller than the axial depth of the groove26.

FIG. 5is a plan view of the base member21, showing a state that the wiring substrate14is arranged on the base member21. If the wiring substrate14is arranged on the base member21as shown inFIGS. 1 and 5, the arc portion141is arranged within the second accommodation portion214. The extension portion142is arranged within the third accommodation portion215. The extension portion142is arranged on the lower surface of the base member21through the step portion241and the opening portion24. At least a portion of the extension portion142arranged on the lower surface of the base member21is also arranged in the groove26. In other words, the extension portion142extends from the upper surface of the base member21to the lower surface thereof through the second accommodation portion214, the third accommodation portion215, and the opening portion24.

As stated above, the arc portion141preferably corresponds in shape to the second accommodation portion214. For that reason, it is possible to prevent the arc portion141from circumferentially or radially protruding from the second accommodation portion214. The thickness of the arc portion141is preferably equal or substantially equal to or smaller than the axial depth of the second accommodation portion214. This makes it possible to prevent the arc portion141from axially protruding from the second accommodation portion214. It is therefore possible to prevent the arc portion141from making contact with the stator22and to reduce the axial dimension of the motor1.

As shown inFIGS. 1 and 5, the extension portion142is preferably accommodated within the third accommodation portion215. For that reason, it is possible to prevent the extension portion142from protruding upward beyond the upper surface of the base member21. Since the thickness of the extension portion142is equal to or smaller than the axial depth of the third accommodation portion215, the extension portion142is prevented from axially protruding from the third accommodation portion215. Thus, the extension portion142is prevented from making contact with the remaining portions of the motor1. This preferably makes it possible to reduce the axial dimension of the motor1. The thickness of the extension portion142is preferably equal or substantially equal to the axial depth of the groove26or smaller than the axial depth of the groove26. For that reason, the extension portion142extending through the groove26does not protrude axially downward from the lower surface of the base member21. The extension portion142is positioned within the thickness (i.e., the axial dimension) of the base member21having a flat shape. Thus, the overall axial dimension of the motor1can be reduced just as much as the thickness of the wiring substrate14.

As shown inFIG. 3, a fourth accommodation portion216is preferably arranged on the lower surface of the base member21and is positioned at the axial opposite side from the first accommodation portion212. The fourth accommodation portion216is a region depressed toward the lower surface of the base member21. When viewed axially, the fourth accommodation portion216has a substantially annular shape about the center axis J1. The through-holes2121extending through the second accommodation portion214also extends through the fourth accommodation portion216. The fourth accommodation portion216is arranged radially between the groove26and the opening of the tubular portion211.

When a base unit is assembled by attaching the stator22and the like to the base member21as shown inFIG. 1, the fourth accommodation portion216is preferably sealed by a substantially flat seal member50. The seal member50corresponds in shape to the fourth accommodation portion216. The axial depth of the fourth accommodation portion216is equal or substantially about equal to the axial dimension of the seal member50or larger than the axial dimension of the seal member50. When the fourth accommodation portion216is sealed by the seal member50, it is preferably possible to prevent the seal member50from axially protruding from the fourth accommodation portion216. This makes it possible to reduce the axial dimension of a motor1or a disk drive apparatus.

A plurality of lead wires2221led out from the coils222are connected to the arc portion141of the wiring substrate14. In the present preferred embodiment, three lead wires2221are preferably connected to the arc portion141because the motor1preferably is a three-phase motor, for example. In the present preferred embodiment, the lead wires2221are preferably connected to the arc portion141by soldering. Alternatively, the lead wires2221may be connected to the arc portion141by any other desirable methods.

The connecting portions51of the arc portion141and the lead wires2221are respectively arranged within the through-holes2121of the second accommodation portion214. The axial lower ends of the connecting portions51are positioned axially higher than the bottom of the fourth accommodation portion216. For that reason, when the fourth accommodation portion216is sealed by the seal member50, the connecting portions51are preferably prevented from making contact with the seal member50. Similarly, the connecting portions51are prevented from protruding axially downward beyond the lower surface of the base member21. Since the fourth accommodation portion216and the through-holes2121are respectively sealed by the seal member50, dust or the like is prevented from entering the inside of the motor1through the fourth accommodation portion216or the through-holes2121.

The base member21is preferably formed by, for example, a process including press working. First, a flat raw member is arranged within a progressive mold. A series of press workings is performed with respect to the raw member, thereby forming the base member21which includes the tubular portion211, the first accommodation portion212, the second accommodation portion214, the third accommodation portion215, the opening portion24, the through-holes2121, the coil accommodation portions213, and so forth.

In the base member21subjected to the press workings, a cutting is preferably carried out on the inner surface of the tubular portion211. Thus, the inner surface of the tubular portion211becomes smooth. This makes it possible to smoothly insert the sleeve41and to prevent deformation or clogging of the sleeve41during a press-fitting process of the sleeve41. The cutting may be performed on the portions other than the tubular portion211. For example, within the mold, portions other than the tubular portion211, such as the entire upper and lower surfaces of the base member21, the first accommodation portion212, the second accommodation portion214, the third accommodation portion215, and the fourth accommodation portion216, may be subjected to cutting as well as a press working.

In the base member21subjected to the press working, undercuts or burrs are formed in the peripheral edge of the opening of the tubular portion211, the ends of the through-holes2121, the opening portion24, or the outer edge of the base member21by punching the raw member with the mold. In particular, a cutting may be performed with respect to the burrs formed by the press work. If the burrs are removed by the cutting, the peripheral edge of the tubular portion211and the end of the opening portion24preferably become smooth. Therefore, when assembling the base member21, the components such as the stator22and the like can be attached with substantially no likelihood of damage. By performing the press working, an undercut is formed at the end of the tubular portion211on the lower surface of the base member21.

A plating work is preferably performed with respect to the base member21which has been subjected to the press working and the cutting. For example, nickel-based metal is preferably used as the plating metal. By virtue of the plating work, the base member21is completely covered with a thin film of the plating metal. The thickness of the thin film may preferably be, e.g., from about 2 μm to about 10 μm. Accordingly, it is possible to prevent the base member21from being corroded by the lubricant of the bearing mechanism4or due to the external environment.

In the base member21subjected to the plating work, the thickness of the thin film at the end of the opening portion24is larger than the thickness of the thin film on the upper surface of the base member21. Accordingly, when the wiring substrate14extends toward the upper surface and the lower surface of the base member21through the opening portion24, it is preferably possible to prevent the wiring substrate14from being damaged by the end of the opening portion24or the step portion241.

While a preferred embodiment of the present invention has been described above, the present invention can be modified in many other different forms.

For example, only one through-hole2121may be arranged in the second accommodation portion214. In that case, the lead wires2221extending from the respective coils222are led to the single through-hole2121and are connected to the arc portion141by soldering or other desirable methods. Therefore, as compared with a case where a plurality of through-holes2121is provided, it is possible to increase the rigidity of the base member21.

Even in case where a plurality of through-holes2121is arranged in the second accommodation portion214, there may exist the through-hole2121to which the lead wires2221are led and the through-hole2121to which the lead wires2221are not led.

The second accommodation portion214may not have a recess shape but may alternatively be a through-hole axially extending through the base member21. In that case, it is preferred that a brim portion be arranged in at least a portion of the inner surface of the second accommodation portion214. The brim portion radially protrudes from the inner surface of the second accommodation portion214. At least one brim portion may be arranged in the peripheral edge of the second accommodation portion214. Also, a plurality of brim portions may be arranged in the peripheral edge of the second accommodation portion214if so desired. At least one brim portion may be arranged to surround the second accommodation portion214. Therefore, when the wiring substrate14is arranged on the base member21, the brim portions can axially support the arc portion141of the wiring substrate14.

FIG. 6is a partial section view of a motor in accordance with a modified example of a preferred embodiment of the present invention.FIG. 7is a plan view of a base part21A in accordance with a modified example of a preferred embodiment of the present invention, showing the tubular portion211and its vicinities. The same configuration as the aforementioned base member21will be designated by like reference symbols and will not be described herein below.

As shown inFIGS. 6 and 7, the base member21A preferably includes a second through-hole portion214A. The second through-hole portion214A axially extends through the base member21A. The second through-hole portion214A is arranged radially outward of the tubular portion211. When seen axially, the contour of the second through-hole portion214A preferably has a substantially arc-like shape. The contour of the second through-hole portion214A extends in the circumferential direction along the tubular portion211.

As shown inFIGS. 6 and 7, at least one brim portion2141is arranged on the inner surface214A1of the second through-hole portion214A. When the motor1is assembled, the brim portion2141axially supports the arc portion141of the wiring substrate14. In this modified example, two brim portions2141are preferably respectively arranged in the radial outer region and the radial inner region of the inner surface214A1. In other words, a pair of brim portions2141radially opposed to each other is arranged on the inner surface214A1. The brim portions2141extend in the circumferential direction along the inner surface214A1. When viewed axially, the contour of each of the brim portions2141extending in the circumferential direction has a substantially arc-like shape.

Brim portions2141are also preferably arranged in one circumferential end region and the other circumferential end region of the inner surface214A1. In other words, at least one pair of brim portions2141opposed to each other in the circumferential direction is arranged on the inner surface214A1. When viewed axially, the contour of the brim portions2141opposed to each other in the circumferential direction is rectangular or substantially rectangular.

The respective brim portions2141extend from the inner surface214A1in the direction perpendicular or substantially perpendicular to the center axis J1. In the example shown inFIG. 7, the brim portions2141extend in at least one of the radial direction and the circumferential direction.

At least one of the brim portions2141is opposed to at least one of the coils222in a spaced-apart relationship. In the example shown inFIG. 6, the brim portions2141are axially opposed to the coils222. On the inner surface214A1, the axial positions of the respective brim portions2141remain the same. Accordingly, when the wiring substrate14is arranged in the second through-hole portion214A, the wiring substrate14extends parallel or substantially parallel to the direction perpendicular to the center axis J1.

The number, position and shape of the brim portions2141are not particularly limited. A plurality of brim portions2141may be arranged on the inner surface214A1of the second through-hole portion214A in a spaced-apart relationship along the circumferential direction. When viewed axially, one brim portion2141may be arranged in a substantially ring-like shape along the inner surface214A1of the second through-hole portion214A. The brim portions2141may have an identical shape or different shapes. The shape of the brim portions2141may be an arc shape, a polygonal shape, a circular shape, an elliptical shape or the combination thereof. However, the shape of the brim portions2141is not particularly limited thereto.

The second accommodation portion214may be the second through-hole portion214A. The third accommodation portion215may be a through-hole portion axially extending through the base member21A. In the example shown inFIG. 7, the base member21A preferably includes a third through-hole portion215A. At least one brim portion2151is arranged on the inner surface215A1of the third through-hole portion215A. The brim portion2151protrudes from the inner surface215A1of the third through-hole portion215A in the circumferential direction and extends in the radial direction. Referring toFIG. 7, two brim portions2151are circumferentially opposed to each other in a spaced-apart relationship. When viewed axially, the contour of the brim portions2151is rectangular or substantially rectangular. On the inner surface215A1, the axial positions of the brim portions2151remain the same. Accordingly, when the wiring substrate14is arranged on the base member21A, the extension portion142extends parallel or substantially parallel to the direction perpendicular to the center axis J1. In the example shown inFIG. 7, the second through-hole portion214A is joined to the third through-hole portion215A, thereby defining a single through-hole portion. The second through-hole portion214A need not be necessarily joined to the third through-hole portion215A.

The number, position and shape of the brim portions2151is not particularly limited. A plurality of brim portions2151may be arranged in at least one of one circumferential end region and the other circumferential end region of the inner surface215A1of the third through-hole portion215A in a spaced-apart relationship. The brim portions2151arranged within the third through-hole portion215A may be connected to the brim portions2141arranged within the second through-hole portion214A. In that case, when viewed axially, the brim portions2151may be connected to the brim portions2141so as to define a substantially ring-like shape. At least a portion of the brim portions2151may be connected to at least a portion of the brim portions2141. The brim portions2151may be arranged in a spaced-apart relationship with the brim portions2141. The brim portions2151may have an identical shape or different shapes. The shape of the brim portions2151may be an arc shape, a polygonal shape, a circular shape, an elliptical shape, or the combination thereof. However, the shape of the brim portions2151is not particularly limited thereto. The shape of the brim portions2151may alternatively be identical with the shape of the brim portions2141or may differ from the shape of the brim portions2141.

Referring toFIGS. 2 and 3, the circumferential width of the opening portion24is preferably equal or substantially equal to the circumferential width of the groove26. However, the circumferential width of the opening portion24need not be necessarily equal to the circumferential width of the groove26. The circumferential width of the opening portion24may differ from the circumferential width of the groove26.

FIG. 8is a perspective view of a base member21B according to another modified example of a preferred embodiment of the present invention, which is seen at the axial lower side. Referring toFIG. 8, an opening portion24B extends in the circumferential direction. The circumferential width of the opening portion24B is larger than the circumferential width of the groove26. Accordingly, when assembling the motor1, the extension portion142of the wiring substrate14can easily pass through the opening portion24B. As a result, it is possible to reduce the time required in assembling the motor1.

As shown inFIGS. 2 and 3, when viewed axially, the through-holes2121preferably have an identical contour. However, the through-holes2121may differ in contour from one another. The through-holes2121may differ in size and orientation from one another.

FIG. 9is a partially enlarged plan view of a base member21C according to a further modified example of a preferred embodiment of the present invention. As shown inFIG. 9, when viewed axially, each of the through-holes2121has a region where the dimension in the direction perpendicular or substantially perpendicular to the center axis J1becomes largest. In other words, when viewed axially, each of the through-holes2121has a contour extending in at least one direction. Referring toFIG. 9, when viewed axially, the direction in which the dimension of the contour of the through-holes2121becomes largest is the longitudinal direction. In the through-holes2121, this direction will be referred to as “longitudinal direction”. When viewed axially, the direction in which the through-holes2121face toward the tubular portion211is the longitudinal direction. InFIG. 9, the longitudinal directions of the through-holes2121are respectively indicated by broken lines L. When viewed axially, the longitudinal directions (indicated by the broken lines L) of the through-holes2121are parallel or substantially parallel to one another. Accordingly, when assembling the motor1, the lead wires2221of the respective phases can be led out from the through-holes2121in a parallel or substantially parallel relationship with one another. As a result, it is possible to reduce the time required in assembling the motor1.

The extension directions (longitudinal directions) of the contours of the through-holes2121may be identical with one another or may differ from one another. The through-holes2121may include a plurality of through-holes2121identical in the extension directions of the contours thereof. The through-holes2121may include a plurality of through-holes2121differing in the extension directions thereof. The longitudinal widths of the through-holes2121may be equal to one another or may differ from one another. The through-holes2121may include through-holes equal in the longitudinal width and through-holes differing in the longitudinal width. In the plane perpendicular or substantially perpendicular to the center axis J1, the widths of the through-holes2121in the direction perpendicular to the longitudinal direction may be equal to one another or may differ from one another. In the plane perpendicular or substantially perpendicular to the center axis J1, the widths of the through-holes2121in the longitudinal direction may be equal to, or may differ from, the widths of the through-holes2121in the direction perpendicular or substantially perpendicular to the longitudinal direction.

In the foregoing preferred embodiment, three-phase lead wires2221of U, V, and W phases preferably are all connected to the wiring substrate14. In that case, a common wire is connected to the three lead wires2221at the side of the stator22but is not directly connected to the wiring substrate14. Alternatively, the common wire may be connected to the wiring substrate14in place of the stator22. In that case, the number of the through-holes2121arranged in the second accommodation portion214can be set to four, including the ones for the three lead wires2221and the one for the common wire. As long as short circuit or mutual contact is prevented, one of the common wire and the three lead wires2221may be arranged within each of the through-holes2121together with the remaining lead wires2221. This configuration makes it possible to reduce the number of the through-holes2121. As a result, it is possible to prevent the reduction of rigidity of the base member21otherwise caused by the arrangement of the through-holes2121.

The motor1of the foregoing preferred embodiments preferably is a three-phase motor. However, the number of phases of the motor1need not be particularly limited. For example, it may be possible to provide a single-phase motor or a multiple-phase motor such as a five-phase motor or a seven-phase motor. In that case, the number of the through-holes2121arranged in the second accommodation portion214may be changed in conformity with the number of the lead wires2221or the treatment method of the common wire.

Preferred embodiments of the present invention can be used in a motor for a disk drive apparatus or in a motor for other applications than the disk drive apparatus.