JP2013118024A - Spindle motor and disk clamp mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spindle motor such that a clamper having the same shape can be used irrespective of the shape of a disk guide on a turntable side and a clamp magnet is prevented from falling off.SOLUTION: A cylindrical member 28 includes: a peripheral portion 28a that is inserted into and engaged with a positioning hole 31a of a clamper 30A; and a first lower surface portion 28c that faces a clamp magnet 27 in an axial direction, and is fixed to an upper portion of a rotation axis 22.

Description

  The present invention relates to a spindle motor and a disk clamp mechanism for rotating an optical disk, a magneto-optical disk, and the like.

  A disk drive device provided with a head mechanism for reading information recorded on a disk or writing information on a disk is known as an optical disk device such as a CD, a DVD, or an MD, or a magneto-optical disk device.

In the disk drive device, it is necessary to hold the disk in pressure contact with a turntable of a spindle motor that rotates the disk.
For this reason, a clamper that contacts the upper surface of the disk placed on the turntable is provided in the disk drive device, and a clamping magnet for attracting the clamper is provided in the center of the turntable of the spindle motor. ing.
Further, in the disk drive device, it is necessary to position (center) the clamper with respect to the turntable. For example, Patent Document 1 discloses a device as shown in FIGS.

FIG. 8 shows a state before the clamper is attracted to the turntable, and FIG. 9 shows a state where the clamper is attracted to the turntable.
As shown in the figure, the spindle motor 131 has a motor main body 132 and a rotating shaft 133, and a turntable 134 on which the optical disk 150 is placed is attached to the rotating shaft 133.
The turntable 134 has a mounting surface 135 on which the optical disk 150 is mounted on the outer periphery. A disk guide 137 that protrudes upward from the mounting surface 135 is formed on the inner peripheral side of the mounting surface 135. The disc guide 137 is fitted into the center hole 151 of the optical disc 150 to position the optical disc when the optical disc 150 is placed on the placement surface 135.

A recess 138 is formed on the inner peripheral side of the disk guide 137. In the recess 138, a clamp magnet 139 that attracts the clamper 145 and a yoke 140 for suppressing the magnetic resistance of the clamp magnet 139 are provided.
Further, on the inner peripheral side of the disk guide 137, an insertion hole 141 is provided at a substantially central portion of the turntable 134 and through which the rotation shaft 133 of the spindle motor 131 is inserted. A rotation shaft 133 of a spindle motor is attached to the insertion hole 141, and the turntable 134 is rotated together with the rotation shaft 133.

The clamper 145 that holds the optical disk 150 together with the turntable 134 has a through hole 146 through which a locking convex portion 129 provided in the cover 128 that constitutes a part of the housing of the optical disk apparatus is inserted. Is provided.
In the clamper 145, a locking projection 129 provided on the cover 128 is inserted into the through hole 146, and the locking piece 147 is locked by a stopper 130 attached to the distal end side of the locking projection 129. Thus, the upper cover 128 is movably attached.
On the outer peripheral side of the locking piece 147, a positioning convex portion 148 for positioning the clamper 145 with respect to the turntable 134 is provided.
The clamper 145 is positioned with respect to the turntable 134 by fitting the positioning convex portion 148 along the inner periphery of the concave portion 138 provided in the turntable 134.
Further, the clamper 145 is formed with a disk pressing portion 149 that contacts the optical disk 150 and sandwiches the optical disk 150 together with the mounting surface 135 on the outer peripheral side corresponding to the mounting surface 135 of the turntable 134.

As described above, by accurately positioning the clamper 145 with respect to the turntable 134, eccentricity when the optical disk 150 is rotated can be suppressed, and recording / reproduction with respect to the optical disk 150 can be performed appropriately.
Further, when the clamper 145 is attracted to the turntable 134, the optical disc 150 is sandwiched between the disc pressing portion 149 of the clamper 145 and the mounting surface 135 of the turntable 134. Can be stably held by the turntable 134 and the clamper 145.

JP 2000-156007 A

  However, in the structure in which the clamper 145 is positioned by fitting the concave portion 138 on the inner peripheral side of the disc guide 137 and the convex portion 148 of the clamper 145 as in the conventional device, for example, the shape of the disc guide 137 needs to be changed. When this occurs, it is necessary to change the clamper 145 as well, resulting in a problem of a significant increase in cost.

In addition, although the clamping magnet 139 and the yoke 140 are fixed in the recess 138 with an adhesive or the like, for example, if the adhesive strength is reduced due to the deterioration of the adhesive or the like, the impact due to the magnetic attraction when the disk is attached or detached, There is a risk that the clamping magnet 139 may peel off and be detached from the turntable due to vibration caused by high-speed rotation.
When the clamp magnet 139 is detached from the turntable, the clamp magnet 139 is attracted to the clamper 145 in the above-described conventional apparatus, and the optical disk 150 cannot be gripped by the turntable 134 and the clamper 145, and the stable disk Cannot be driven.

  Accordingly, the present invention is intended to provide a spindle motor and a disk clamp mechanism that can solve the problems of the conventional techniques as described above.

In order to solve the above problems, the spindle motor of the present invention is
A spindle motor comprising a turntable on which a disk is placed and rotates integrally with a rotating shaft,
A disc guide for guiding the inner edge of the disc;
A clamping magnet disposed on the inner diameter side of the disk guide;
A cylindrical member fixed to the upper part of the rotating shaft,
The cylindrical member has an outer peripheral portion inserted into a positioning hole or a positioning concave portion of the clamper, and a first lower surface portion facing the clamping magnet in the axial direction.

In the spindle motor of the present invention, the cylindrical member has a second lower surface portion on the inner diameter side of the first lower surface portion, and the second lower surface portion faces the disk guide in the axial direction. Is preferred.
Moreover, it is preferable that the said cylindrical member has an inclined surface in the upper part of the said outer peripheral part, and the outer diameter is reducing gradually upwards.
Furthermore, the cylindrical member is preferably made of a nonmagnetic material.

  The disc clamp mechanism of the present invention includes the spindle motor of the present invention and the clamper that is positioned above the spindle motor and is attracted to the clamp magnet, and the clamper is an outer peripheral portion of the cylindrical member. It is characterized by having the positioning hole or the positioning recess corresponding to.

In this invention, the cylindrical member which has the outer peripheral part inserted by the positioning hole or positioning recessed part of a clamper, and the 1st lower surface part which faces a clamp magnet in an axial direction is being fixed to the upper part of a rotating shaft. .
Therefore, even when it is necessary to change the shape of the disc guide on the turntable side, the clamper can be positioned without changing the shape of the clamper.
Further, even if the clamping magnet is lifted from the turntable side, the cylindrical member prevents the clamping magnet from falling off, and the disk can be driven stably.

It is a side view of the spindle motor M1 which concerns on the 1st Example of this invention, and has shown the paper surface right half with the cross section. The cylindrical member in the spindle motor M1 of FIG. 1 is shown, (a) is a top view, (b) is sectional drawing cut | disconnected along the AA in (a). 2A and 2B are cross-sectional views showing a main part of a disc clamping mechanism using the spindle motor M1 of FIG. 1, wherein FIG. 1A shows a state before the optical disc is gripped, and FIG. 2B shows a state where the optical disc is gripped. Yes. It is sectional drawing which shows the principal part of another disk clamp mechanism of this invention, (a) shows the state before an optical disk is gripped, (b) has shown the state by which the optical disk was gripped. It is a side view of the spindle motor M2 which concerns on the 2nd Example of this invention, and has shown the paper surface right half with the cross section. The cylindrical member in the spindle motor M2 of FIG. 5 is shown, (a) is a top view, (b) is sectional drawing cut | disconnected along the BB line in (a). FIG. 6 is a cross-sectional view showing a main part of a disc clamping mechanism using the spindle motor M2 of FIG. 5, wherein (a) shows a state before the optical disc is gripped, and (b) shows a state where the optical disc is gripped. Yes. It is a longitudinal cross-sectional view which shows the disk rotation drive part of the disk drive apparatus of a prior art example, and has shown the state before an optical disk is gripped. It is a longitudinal cross-sectional view which shows the disk rotation drive part of the disk drive apparatus of a prior art example, and has shown the state in which the optical disk was hold | gripped.

  Hereinafter, embodiments of the present invention will be exemplarily described based on the drawings.

(First embodiment)
The configuration of the spindle motor according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a side view showing the spindle motor M1 of this example, and shows the right half of the drawing in section.
The spindle motor M1 is mainly composed of a stator S and a rotor R.

  The stator S includes a bearing portion including a bearing holder 12 and a bearing 13, a stator core 14 disposed around the bearing portion, a core cover 15, and a coil 16.

The bearing holder 12 is fixed to a base 11 on which a so-called iron substrate or printed wiring board having a printed circuit formed on its surface is attached by overlapping an iron plate.
The bearing 13 is obtained by impregnating a cylindrical sintered metal with lubricating oil, and is fixed to the inner peripheral side of the bearing holder 12 by press fitting or the like.
A Hall element (not shown) is provided on the base 11 so as to face a driving magnet 25 described later, and the rotation of the rotor R can be detected by the Hall element. .

The stator core 14 is composed of a laminated body of plate cores on which a plurality of salient poles are formed, and is fixed to the outer periphery of the bearing holder 12.
A core cover 15 made of an insulating resin is disposed on the surface of the stator core 14, and a coil 16 is wound through the core cover 15.

  The rotor R includes a rotating shaft 22 that is rotatably supported by a bearing portion, a rotor case 21 that rotates integrally with the rotating shaft 22, and a driving magnet 25 that is fixed to the rotor case 21.

The rotor case 21 is formed of a magnetic plate material in a cap shape, and has a cylindrical portion 21a that is formed in a cylindrical shape coaxially with the rotary shaft 22 and an upper surface portion 21b that has a slightly lower inner diameter side.
The rotation shaft 22 is fixed by press-fitting to a burring portion 21 c provided at the center of the upper surface portion 21 b of the rotor case 21, and is supported by the bearing 13 in a rotatable state.

A cylindrical driving magnet 25 that is opposed to the salient poles of the stator core 14 in the radial direction is attached to the inside of the cylindrical portion 21 a of the rotor case 21. The drive magnet 25 is magnetized in a plurality of NS directions alternately in the circumferential direction.
An upper surface portion 21 b of the rotor case 21 is a turntable on which a disk is detachably disposed and rotates integrally with the rotary shaft 22.
A disk guide 23 is disposed on the inner diameter side of the upper surface portion 21b, and a friction sheet 24 is disposed on the outer diameter side of the upper surface portion 21b.

The disk guide 23 is a member for guiding the disk concentrically with the rotary shaft 22, and an upright portion 23 a on the inner diameter side is fixed to the outer periphery of the burring portion 21 c of the rotor case 21 by press-fitting.
The disk guide 23 is made of hard resin, has a recess 23b on the outer periphery of the upright portion 23a, and a plurality of guide claws 23c are provided at equal intervals in the rotation direction on the outer periphery of the recess 23b. The guide claw 23c comes into contact with the inner edge of the center hole of the disk.

A yoke plate 26 and a clamping magnet 27 are disposed in the recess 23 b of the disk guide 23. The yoke plate 26 and the clamping magnet 27 are both formed in an annular shape.
The yoke plate 26 serves as a back yoke for the clamping magnet 27 and is made of a magnetic material.
The clamp magnet 27 magnetically attracts a clamper described later and attracts the clamper toward the turntable.

A cylindrical member 28 is press-fitted into the upper portion of the rotating shaft 22.
As shown in FIG. 2, the cylindrical member 28 of the present example has an inclined surface 28b on the upper side of the outer peripheral portion 28a, and the outer diameter gradually decreases upward. As will be described in detail later, the outer peripheral portion 28a including the inclined surface 28b serves to center the clamper.
In addition, the lower surface of the cylindrical member 28 of this example is stepped, and has a first lower surface portion 28c on the outer diameter side and a second lower surface portion 28d on the inner diameter side lower than the first lower surface portion 28c. Yes.

As shown in FIG. 1, the outer diameter of the outer peripheral portion 28 a of the cylindrical member 28 is larger than the inner diameter of the clamping magnet 27, and the first lower surface portion 28 c of the cylindrical member 28 is It has a structure that faces the upper surface in the axial direction.
Therefore, in the spindle motor M1 of this example, even if the yoke plate 26 and the clamp magnet 27 are lifted from the recess 23b of the disk guide 23, the first lower surface portion 28c of the cylindrical member 28 is the upper surface of the clamp magnet 27. The spindle magnet 27 can be prevented from falling off, so that the spindle motor is highly reliable.

Further, the second lower surface portion 28d of the cylindrical member 28 faces the upright portion 23a of the disk guide 23 in the axial direction. In this example, the second lower surface portion 28d is in contact with the upper end of the upright portion 23a.
For this reason, in the spindle motor M1 of this example, the disk guide 23 can be prevented from being lifted, and the spindle motor becomes more reliable.

In the spindle motor of the present invention, the material of the cylindrical member 28 is not particularly limited, but a nonmagnetic material is preferable to a magnetic material, and a nonmagnetic material such as brass (brass) having excellent durability and workability. Metal materials are particularly preferred.
The reason is that since the outer diameter of the outer peripheral portion 28a of the cylindrical member 28 is larger than the inner diameter of the clamping magnet 27, the cylindrical member 28 needs to be assembled to the rotary shaft 22 after the clamping magnet 27 is assembled. This is because if the cylindrical member 28 is made of a magnetic material, an extra attractive force is received from the clamping magnet 27 during assembly, making it difficult to assemble.

  Next, a disk clamping mechanism using the spindle motor M1 of this example will be described with reference to FIG. FIG. 3A shows a state before the optical disc is gripped, and FIG. 3B shows a state where the optical disc is gripped.

In FIG. 3, 30A is a clamper and 40 is an optical disk.
The spindle motor M1 and the clamper 30A are appropriately supported in a housing of a disk drive device (not shown).
The clamper 30A is located above the spindle motor M1, has a disk-like shape as a whole, and at least a portion facing the clamp magnet 27 is formed of a magnetic material.
In the center of the clamper 30A, a positioning hole 31a having an inner diameter slightly larger than the outer diameter of the outer peripheral portion 28a of the cylindrical member 28 is provided.
A disc pressing portion 32 is provided on the outer periphery of the clamper 30A.

As shown in FIG. 3A, when the optical disc 40 is conveyed between the spindle motor M1 and the clamper 30A, the spindle motor M1 is raised.
Then, as shown in FIG. 3B, the plurality of guide claws 23c of the disk guide 23 are brought into contact with the inner edge portion of the center hole 40a of the optical disk 40, and the optical disk 40 is automatically centered.
On the other hand, the clamper 30A is attracted by the clamping magnet 27, and is automatically centered by guiding the positioning hole 31a along the inclined surface 28b and the outer peripheral portion 28a of the cylindrical member 28. In addition, since the upper side of the outer peripheral portion 28a of the cylindrical member 28 of this example is an inclined surface 28b whose outer diameter gradually decreases upward, even if the centers of the clamper 30A and the rotating shaft 22 are slightly shifted, The clamper 30A is appropriately centered along the inclined surface 28b.
Thereby, the disc pressing portion 32 of the clamper 30A stably holds the optical disc 40 between the upper surface portion 21b of the rotor case 21 and suppresses eccentricity when the optical disc 40 is rotated by driving the spindle motor M1. Thus, recording / reproduction with respect to the optical disc 40 can be performed appropriately.

  In the disc clamp mechanism of FIG. 3, the clamper 30A having the positioning hole 31a is used. For example, a clamper 30B having the positioning recess 31b may be used as shown in FIG. The inner diameter of the positioning recess 31 b is slightly larger than the outer diameter of the outer peripheral portion 28 a of the cylindrical member 28.

However, in the structure in which the clamper is centered by fitting the positioning recess 31b of the clamper 30B and the outer peripheral portion 28a of the cylindrical member 28 as shown in FIG. 4, the centering accuracy tends to vary slightly. The reason is that, in general, the clamper often requires uneven processing in addition to the centering positioning recess 31b, so it is difficult to strictly control the inner diameter of the centering positioning recess 31b, and the inner diameter varies. It is because it is easy to occur.
On the other hand, as shown in FIG. 3, in the structure in which the clamper is centered by fitting the positioning hole 31a of the clamper and the outer peripheral portion 28a of the cylindrical member 28, variations in centering accuracy can be suppressed. The reason is that the positioning hole 31a can easily manage the dimensions regardless of the uneven shape of the clamper.
Therefore, in the disc clamping mechanism of the present invention, the configuration of FIG. 3 is more preferable than the configuration of FIG.

As described above, in the spindle motor and the disk clamping mechanism of this example, the outer peripheral portion 28a inserted into the positioning hole 31a (see FIG. 3) or the positioning recess 31b (see FIG. 4) of the clamper, the clamping magnet 27, A cylindrical member 28 having a first lower surface portion 28 c facing in the axial direction is fixed to the upper portion of the rotating shaft 22.
For this reason, even when it is necessary to change the shape of the disk guide, the clamper can be positioned by the cylindrical member without changing the clamper. That is, the clamper having the same shape can be used regardless of the shape of the disk guide on the turntable side. Further, even when the clamp magnet is lifted from the turntable side, the cylindrical member prevents the clamp magnet from falling off, and the disk can be driven stably.

(Second Embodiment)
Next, the configuration of the spindle motor according to the second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a side view showing the spindle motor M2 of this example, and shows the right half of the drawing in section.
In FIG. 5, the same members as those in FIG. 1 are denoted by the same reference numerals, and the description of these members is omitted.

  The spindle motor M2 of this example is mainly different from the spindle motor M1 of FIG. 1 in the shapes of the rotor case, the disk guide, and the cylindrical member.

  The rotor case 51 of this example is formed of a magnetic plate material in a cap shape, and includes a cylindrical portion 51a formed in a cylindrical shape coaxially with the rotary shaft 22 and a flat plate-shaped upper surface portion 51b. The rotating shaft 22 is fixed to a burring portion 51 c provided at the center of the upper surface portion 51 b of the rotor case 51.

The disk guide 53 of this example is formed of a hard resin in an annular shape, and a plurality of guide claws 53c are provided at equal intervals in the rotation direction on the outer peripheral side, and a plurality of protrusions 53d are provided on the lower surface. Yes. The inner diameter portion of the disk guide 53 is a through hole.
The disc guide 53 is integrated with the rotor case 51 by inserting protrusions 53 d into a plurality of through holes provided in the upper surface portion 51 b of the rotor case 51 and thermocompression bonding.

  The clamping magnet 27 is disposed in the through hole portion of the disk guide 53 and is directly disposed on the upper surface portion 51 b of the rotor case 51. For this reason, the rotor case 51 becomes the back yoke of the clamping magnet 27, and the yoke plate 26 in FIG. 1 is not required in the spindle motor M2 of this example.

  As shown in FIG. 6, the cylindrical member 58 of the present example has a curved inclined surface 58 b on the upper side of the outer peripheral portion 58 a parallel to the axial direction, and the outer diameter gradually decreases upward. Moreover, the lower surface of the cylindrical member 58 is a flat first lower surface portion 58c.

As shown in FIG. 5, the outer diameter of the outer peripheral portion 58 a of the cylindrical member 58 is larger than the inner diameter of the clamping magnet 27, and the first lower surface portion 58 c of the cylindrical member 58 is It has a structure that faces the upper surface in the axial direction.
For this reason, the spindle motor M2 of the present example can prevent the clamp magnet 27 from falling off as with the spindle motor M1, and is a highly reliable spindle motor.

  Next, a disk clamping mechanism using the spindle motor M2 of this example will be described with reference to FIG. FIG. 7A shows a state before the optical disc is gripped, and FIG. 7B shows a state where the optical disc is gripped.

In FIG. 7, the same members as those in FIG. 3 are denoted by the same reference numerals, and description of these members is omitted.
As shown in FIG. 7A, when the optical disc 40 is conveyed between the spindle motor M2 and the clamper 30A, the spindle motor M2 is raised.
Then, as shown in FIG. 7B, the guide claw 53c of the disc guide 53 is brought into contact with the inner edge portion of the center hole 40a of the optical disc 40, and the optical disc 40 is automatically centered.
On the other hand, the clamper 30A is attracted by the clamping magnet 27 and is automatically centered by guiding the positioning hole 31a along the inclined surface 58b and the outer peripheral portion 58a of the cylindrical member 58.
Thereby, the disc pressing portion 32 of the clamper 30A stably holds the optical disc 40 between the upper surface portion 51b of the rotor case 51 and suppresses eccentricity when the optical disc 40 is rotated by driving the spindle motor M2. In addition, recording / reproduction with respect to the optical disc 40 can be performed appropriately.

  In this example, the clamper 30B having the positioning recess 31b shown in FIG. 4 may be used instead of the clamper 30A.

Thus, in the spindle motor and the disk clamping mechanism of this example, the outer peripheral portion 58a inserted into the positioning hole 31a or the positioning recess 31b of the clamper and the first lower surface portion 58c facing the clamping magnet 27 in the axial direction are provided. A cylindrical member 58 is fixed to the upper part of the rotary shaft 22.
For this reason, even when it is necessary to change the shape of the disk guide, the clamper can be positioned by the cylindrical member without changing the clamper. Further, even when the clamp magnet is lifted from the turntable side, the cylindrical member prevents the clamp magnet from falling off, and the disk can be driven stably.

  Further, in this example, the clamping magnet 27 is disposed in direct contact with the upper surface portion 51b of the rotor case 51, the magnetic rotor case 51 serves as a back yoke, and the yoke plate 26 in FIG. 1 is not required. Therefore, the overall height of the spindle motor can be reduced.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can be implemented by appropriately changing each component within the scope of the gist of the present invention. is there.
For example, in the previous embodiment, the cylindrical members 28 and 58 have through-holes, but may be cap-shaped with the top surface closed.
In the previous embodiment, the cylindrical members 28, 58 have the inclined surfaces 28b, 58b above the outer peripheral portions 28a, 58a. However, the cylindrical members 28, 58 have an inclined surface having the same function at the positioning portion on the clamper side. When provided, the inclined surfaces 28b and 58b are not necessarily provided.
In the previous embodiment, the cylindrical members 28 and 58 are directly press-fitted into the rotating shaft 22, but they are press-fitted into the outer periphery of the burring portions 21c and 51c of the rotor case or the outer periphery of the upright portion 23a of the disk guide. It can also be press-fitted into.

DESCRIPTION OF SYMBOLS 11 Base 12 Bearing holder 13 Bearing 14 Stator core 15 Core cover 16 Coil 21 Rotor case 21a Cylindrical part 21b Upper surface part 21c Burring part 22 Rotating shaft 23 Disc guide 23a Upright part 23b Recessed part 23c Guide claw 24 Friction sheet 25 Driving magnet 26 Yoke plate 27 Clamping magnet 28 Cylindrical member 28a Outer peripheral portion 28b Inclined surface 28c First lower surface portion 28d Second lower surface portion 30A, 30B Clamper 31a Positioning hole 31b Positioning recess 32 Disc holding portion 40 Optical disc 40a Center hole 51 Rotor case 51a Cylindrical portion 51b Upper surface portion 51c Burring portion 53 Disc guide 53c Guide claw 53d Projection portion 58 Cylindrical member 58a Outer peripheral portion 58b Inclined surface 58c First lower surface portion 128 Cover 129 Locking Protruding portion 130 Stopper 131 Spindle motor 132 Motor body 133 Rotating shaft 134 Turntable 135 Placement surface 137 Disc guide 138 Recessed portion 139 Clamping magnet 140 Yoke 141 Insertion hole 145 Clamper 146 Through hole 147 Locking piece 148 Positioning convex portion 149 Disc holding part 150 Optical disc 151 Center hole M1, M2 Spindle motor R Rotor S Stator

Claims (5)

A spindle motor comprising a turntable on which a disk is placed and rotates integrally with a rotating shaft,
A disc guide for guiding the inner edge of the disc;
A clamping magnet disposed on the inner diameter side of the disk guide;
A cylindrical member fixed to the upper part of the rotating shaft,
The cylindrical motor has an outer peripheral portion to be inserted into a positioning hole or a positioning recess of a clamper, and a first lower surface portion facing the clamping magnet in the axial direction. The cylindrical member has a second lower surface portion on the inner diameter side of the first lower surface portion,
The spindle motor according to claim 1, wherein the second lower surface portion faces the disk guide in an axial direction.   The spindle motor according to claim 1, wherein the cylindrical member has an inclined surface at an upper portion of the outer peripheral portion, and an outer diameter gradually decreases upward.   The spindle motor according to claim 1, wherein the cylindrical member is made of a nonmagnetic material. 5. The spindle motor according to claim 1, and the clamper positioned above the spindle motor and attracted to the clamp magnet, the clamper having the positioning hole or the positioning recess. Disc clamp mechanism characterized by

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