JP2008187854A - Spindle motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability by enhancing a bonding force between a base and an attraction plate. <P>SOLUTION: The spindle motor is formed by bonding an attraction plate and a base with an adhesive. The attraction-plate side faces are formed into a tapered shape or a stepped shape. The long-side direction in the attraction-plate end faces is configured to be on the base side. The adhesive protruded from the adhesion face between the attraction plate and the base during adhesion rides on the attraction-plate side faces and is fixed there so as to increase a bonding force between the attraction plate and the base. The long-side direction in the attraction plate end faces is configured to be on the rotor magnet side that faces the long-side direction. The adhesive protruded from the adhesion face between the attraction plate and the base during adhesion stays at the gap between the attraction-plate side face and the base face. Consequently, it prevents the adhesive from going around the attraction-plate end face that faces a rotor magnet. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a spindle motor that rotationally drives a disk-shaped recording medium and a recording / reproducing apparatus including the spindle motor.

  A hard disk drive (HDD) has an excellent function as a storage device capable of recording and reproducing a large amount of data, and not only personal computers but also various home appliances including audiovisual products, those incorporating HDDs have begun to spread. Yes. In HDD, it is necessary to rotate the disk at high speed and with high accuracy, and also because it needs durability (long life) that can withstand long-term use, a spindle motor using a hydrodynamic bearing is used for the motor. Has been.

  In recent years, with the spread of small digital devices such as a small portable music recording / playback apparatus incorporating a HDD and a recording medium for a digital camera, the HDD is required to be further reduced in size and thickness. In order to reduce the size and thickness of the HDD, it is necessary to make the spindle motor that rotates the disk smaller and thinner. A typical conventional example of such a spindle motor is shown in the sectional view of FIG.

  In FIG. 10, the rotor magnet 3 is fixed to the hub 4, the suction plate 1 is opposed to the axial end surface of the rotor magnet 3 in the thrust direction, and the suction plate 1 is fixed to the base 2. .

  For example, the following materials are used for each part. The hub 4 is made of stainless steel (eg, DHS1) or aluminum, the rotor magnet 3 is made of a rare earth-iron-boron magnet material (neodymium-iron-boron, etc.), and the suction plate 1 is made of an iron-based material. A nickel-plated (e.g., SPCC) or stainless steel material having magnetism is used, and an aluminum die-cast material or an iron-based material is used for the base 2.

A disk-shaped recording medium such as a magnetic disk is held on a disk receiving surface 4 a on the outer periphery of the hub 4, and a rotor magnet 3 is provided inside the hub 4. (Here, an outer rotor type spindle motor in which the rotor magnet 3 is disposed on the outer periphery of the stator core 5 will be described. However, an inner rotor type spindle motor in which the rotor magnet 3 is disposed on the inner periphery of the stator core 5 is also applicable. .)
The suction plate 1 is attached to the base 2 so as to face the rotor magnet 3. A stator core 5 around which a coil is wound is attached to the base 2.

When a current is sequentially passed through the stator core 5 around which the coil is wound, a rotating magnetic field is generated between the stator core 5 and the rotor magnet 3, and the hub 4 rotates via the bearing device 7 by receiving a driving force. (Currently, hydrodynamic bearings are the mainstream for bearing devices.)
The stator core 5 and the rotor magnet 3 are arranged with their axial magnetic center positions shifted in order to reduce noise and vibration to generate axial magnetic attraction, as shown in Patent Document 1 A ring-shaped suction plate 1 is disposed on the base 2 near the rotor magnet 3 and generates an axial suction force on the hub 4.

  Further, not only miniaturization but also cost reduction is demanded for recording / reproducing storage devices such as HDDs. For this reason, cost reduction is also demanded for the components constituting the recording / reproducing storage device, and for example, there is a tendency to use more stamped parts than cut parts.

Parts constituting the recording / reproducing apparatus, such as a suction plate, are also produced by pressing, and the side surfaces thereof have a straight shape as shown in FIG.
Japanese Patent Laid-Open No. 2005-155585

  Compared to a hard disk drive built into a general personal computer, the above-mentioned small hard disk drive for portable use may be subjected to a strong impact such as dropping on the floor during use. It has been gaining importance year after year, such as appealing points. Therefore, the spindle motor has been demanded to increase the shock resistance, and the fixing strength of the suction plate 1 and the base 2 needs to be sufficiently high.

  As a conventional method for fixing the suction plate and the base, a fixing method using an adhesive is used. An adhesive is applied to the base, and a suction plate is placed on the adhesive applied to the base. At this time, the adhesive protrudes from the adhesive surface of the suction plate and the base, and the protruded adhesive wraps around the suction plate side surface 1a due to surface tension.

  Conventionally, since the suction plate side surface 1a has a straight shape, the suction plate is attracted to the rotor magnet by the magnetic attraction force of the rotor magnet facing the suction plate when the suction plate is peeled off when a strong impact or vibration is applied. This causes contact and leads to problems such as abnormal characteristics, abnormal noise, and generation of foreign matter as a recording / reproducing apparatus.

  Further, since the miniaturized hard disk drive for the above-described use is required to be further reduced in size and thickness, the spindle motor is also required to be reduced in size and thickness. For example, the suction plate, which is a component constituting the recording / reproducing apparatus, is also required to be thin.

  However, when the suction plate is fixed with an adhesive, if the suction plate is thinned, the adhesive pushed by the suction plate during bonding may protrude to the side of the suction plate and further turn to the end surface side facing the magnet. If the amount of the adhesive that wraps around is large, it causes contact with the rotor magnet facing the suction plate, leading to problems such as abnormal characteristics, abnormal noise, and generation of foreign matter as a recording / reproducing apparatus. Accordingly, there has been a problem that the management of the adhesive application amount becomes more difficult as the suction plate becomes thinner and the productivity is lowered.

  An object of the present invention is to provide a high-quality spindle motor at a low cost.

A spindle motor according to the present invention includes a hub having a disk mounting portion, a rotor magnet fixed to the hub, a stator core wound with a coil facing the rotor magnet in the circumferential direction, and the stator core fixed. It has a suction plate fixed to the base, facing the axial end surface of the rotor magnet, and has a wide portion on at least a part of the side surface of the suction plate.
A hub having a disk mounting portion; a rotor magnet fixed to the hub; a stator core wound with a coil facing the rotor magnet in a circumferential direction; a base to which the stator core is fixed; and the rotor The suction plate is fixed to the base so as to face the end surface in the axial direction of the magnet, and the side surface of the suction plate has a tapered shape whose width increases toward the base side.

  According to this invention, when the adhesive pressed by the suction plate protrudes and adheres to the side surface of the suction plate when the suction plate and the base are bonded, a strong impact or vibration is applied to the recording / reproducing apparatus, and the interface between the suction plate and the adhesive Even if peeling occurs, the adhesive fixed to the side of the suction plate generates an anchor effect (wedge effect), and the suction plate can be prevented from coming into contact with the rotor magnet by being restricted from moving toward the opposing rotor magnet. .

  According to the present invention, the taper shape of the suction plate widens toward the base side, so that the adhesive and the taper portion that stick out and stick to the side surface of the suction plate that is tapered when the suction plate is bonded. Causes an anchor effect (wedge effect).

  Therefore, it can avoid that a suction plate and an adhesive agent contact a rotor magnet.

  A preferred embodiment of the spindle motor of the present invention will be described below with reference to FIGS.

(Embodiment 1)
A spindle motor according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a partial cross-sectional view of the spindle motor according to the first embodiment, which includes a suction plate 1, a base 2, a rotor magnet 3, a hub 4, and a stator core 5 wound with a coil. The suction plate 1 is a ring-shaped member having a tapered shape on the side surface 1a, and is made of an iron-based or stainless-based metal material such as SPCC. A side surface 1 a of the suction plate 1 has a tapered shape, and is formed by an end surface 1 b on the base 2 side fixed by the adhesive 6 and an end surface 1 c on the side facing the rotor magnet 3.
The taper shape can be formed by pressing the ring-shaped member obtained by pressing again to form a taper or leaving a sag on the fractured surface after the pressing.

  A manufacturing process for joining the suction plate 1 and the base 2 shown in FIG. 1 will be described with reference to FIGS. The recording / reproducing apparatus of the first embodiment is provided on the base 2 side to which the end surface 1b which is the long side of the suction plate 1 is bonded.

  In FIG. 2, an adhesive 6 is applied to the base 2. As the adhesive 6, for example, an acrylic or epoxy adhesive is used. These adhesives are excellent in tensile shear adhesive strength and use less outgassing.

  In FIG. 3, the suction plate 1 is placed on the adhesive 6 and pressed to hold the suction plate 1 and the base 2 close to each other. Examples of the pressing method include a method using a weight, a press, or a clamp. For example, the jig temperature is heated to about 100 to 120 ° C., a pressure of 2 to 3 N is applied, and the temperature is maintained for about 5 to 20 minutes.

  At this time, the adhesive 6 pressed against the suction plate 1 by pressurization wraps around and adheres to the suction plate side surface 1a. The adhesive 6 fixed to the suction plate side surface 1a is in a state of riding on the suction plate side surface 1a. In the first embodiment, both suction plate side surfaces 1a are tapered, but the tapered shape is not limited to both suction plate side surfaces 1a, and may be either the inner peripheral side or the outer peripheral side.

  According to the coupling method of the first embodiment, when the suction plate 1 and the adhesive 6 are peeled off, the protruding portion such as the adhesive 6 and the taper portion can generate an anchor effect. Therefore, the coupling force between the suction plate 1 and the base 2 can be greatly increased. As a result, contact between the suction plate 1 and the rotor magnet 3 can be avoided, and abnormal characteristics, abnormal noise, and foreign matter can be avoided in the recording / reproducing apparatus.

Moreover, since the taper shape of the suction plate side surface 1a can be implemented by press working, unnecessary cost increase can be avoided. For example, a stage for performing taper processing on the inner periphery and the outer periphery of the suction plate may be provided after the punching process.
(Embodiment 2)
A spindle motor according to a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, the shape of the suction plate side surface 1a is different from that of the suction plate 1 of the first embodiment. The shape and configuration of the base 2 are substantially the same as those of the first embodiment.

  FIG. 4 is a cross-sectional view of the suction plate 1 of the second embodiment. In FIG. 4, the suction plate 1 has a bowl-shaped step shape on the side surface 1a. Each process subsequent to application of the adhesive 6 to the base 2 is the same as that in the first embodiment.

  In FIG. 5, the adhesive 6 pushed out to the suction plate by pressurization during bonding wraps around and adheres to the suction plate side surface 1a. The adhesive 6 fixed to the suction plate side surface 1a is in a state of riding on the flange formed on the suction plate side surface 1a. In the second embodiment, both the inner peripheral side and the outer peripheral side of the suction plate side surface 1a are stepped, but the step shape is not limited to both the suction plate side surface 1a and is either the inner peripheral side or the outer peripheral side. But it ’s okay. In the second embodiment, the step shape of the side surface 1a of the suction plate is two steps. However, the step shape is not limited to two steps, and may be two or more steps.

The effect is the same as that of the first embodiment also by the coupling method of the second embodiment.
(Embodiment 3)
A recording / reproducing apparatus according to Embodiment 3 of the present invention will be described with reference to FIGS. 6, 7 and 8. FIG. In this example, the shape of the suction plate side surface 1a is different from that of the suction plate 1 of the first and second embodiments. The shape and configuration of the base 2 are substantially the same as those of the first embodiment.

  6 and 7 are cross-sectional views of the suction plate 1 according to the third embodiment. 6 and 7, the suction plate 1 has a shape in which a straight shape and a tapered shape are combined on the side surface 1a. Each process subsequent to application of the adhesive 6 to the base 2 is the same as that in the first embodiment.

  In FIG. 8, the adhesive 6 pushed out to the suction plate by pressurization during bonding wraps around and adheres to the suction plate side surface 1a. The adhesive 6 fixed to the suction plate side surface 1a is in a state of riding on the taper portion of the suction plate side surface 1a. In the third embodiment, both the inner peripheral side and the outer peripheral side of the suction plate side surface 1a are stepped. However, the step shape is not limited to both the suction plate side surface 1a, and either the inner peripheral side or the outer peripheral side is used. Or you can. In addition, when the suction plate is produced by press working, the adhesive that protrudes into the sag portion that occurs at the edge portion may be wrapped around and fixed.

The effect of the coupling method of the third embodiment is the same as that of the first embodiment.
(Other embodiments)
Another embodiment is described in FIGS.
The present embodiment is characterized in that the side surface of the suction plate has a shape portion that widens toward the rotor magnet side.

According to this invention, when the adhesive force between the suction plate and the base is sufficient, the surface tension is increased so that the adhesive pushed by the suction plate at the time of bonding the suction plate and the base rises upward when protruding to the side surface of the suction plate. Therefore, it is very easy to manage the amount of adhesive applied so that the adhesive does not enter the end surface of the suction plate facing the rotor magnet, and the adhesive can be prevented from coming into contact with the rotor magnet.
For example, when the side surface of the suction plate is configured in a tapered shape as shown in FIG. 12, the adhesive that protrudes when the suction plate is bonded hardly rises on the side surface of the suction plate, and the adhesive wraps around the end surface of the suction plate facing the rotor magnet. To prevent that.

According to this invention, when the adhesive force between the suction plate and the base is sufficient, the surface tension is increased so that the adhesive pushed by the suction plate at the time of bonding the suction plate and the base rises upward when protruding to the side surface of the suction plate. Therefore, it is very easy to manage the amount of adhesive applied so that the adhesive does not enter the end surface of the suction plate facing the rotor magnet, and the adhesive can be prevented from coming into contact with the rotor magnet.
The spindle motor of the present embodiment will be described with reference to FIGS. In the present embodiment, the shapes of the suction plate 1 and the base 2 are substantially the same as those of the first, second, and third embodiments. The configuration in which the end surface 1b in the long side direction faces the rotor magnet 3 is different from the configurations of the first, second, and third embodiments.

  In FIG. 12, the adhesive 6 pushed out to the suction plate by pressurization during bonding wraps around and adheres to the suction plate side surface 1a. In this embodiment, the gap formed between the suction plate side surface 1a and the base 2 is gradually widened. In this way, when the adhesive 6 is pushed out to the suction plate 1 by the pressure applied during bonding, the surface tension between the suction plate side surface 1a and the base 2 gradually weakens, so that the adhesive 6 moves toward the suction plate side surface 1a. The amount of wraparound can be suppressed. Therefore, it is possible to prevent the adhesive 6 from adhering to the suction plate end surface 1 b facing the rotor magnet 3.

  In FIG. 12, the suction plate side surface 1a is both tapered, but the taper shape is not limited to both the inner and outer peripheral sides of the suction plate side surface 1a. good. In addition, when the suction plate is manufactured by press working, a punching portion generated at the edge portion may be used.

  13 shows the shape of the suction plate 1 of the second embodiment, and FIGS. 14 and 15 show the shape of the suction plate 1 of the third embodiment. The effect is the same even with these configurations.

  The present invention can be used for mass production of a spindle motor of a storage device capable of recording and reproducing a large amount of data such as a hard disk drive (HDD).

Sectional drawing which shows the state which combined the stator core 5 which wound the suction plate 1, the base 2, the rotor magnet 3, the hub 4, and the coil which are components of the spindle motor of Embodiment 1 of this invention. Sectional drawing which shows the suction plate 1 and the base 2 combined in FIG. Sectional drawing which shows after the adhering of the suction plate 1 and the base 2 combined in FIG. Sectional drawing which shows the suction plate 1 which is a component of the spindle motor of Embodiment 2 of this invention. Sectional drawing which shows after adhesion | attachment of the suction plate 1 and the base 2 which are components of the spindle motor of Embodiment 2 of this invention Sectional drawing which shows the suction plate 1 which is a component of the spindle motor of Embodiment 3 of this invention. Sectional drawing which shows the suction plate 1 which is a component of the spindle motor of Embodiment 3 of this invention. Sectional drawing which shows after the suction plate 1 and the base 2 which are components of the spindle motor of Embodiment 3 of this invention adhere | attach Sectional drawing which shows after the suction plate 1 and the base 2 which are components of the spindle motor of Embodiment 3 of this invention adhere | attach Sectional drawing which shows the structure of the typical spindle motor which has a suction plate Sectional drawing which shows after typical suction plate 1 and base 2 adhesion Sectional drawing which shows the suction plate 1 and the base 2 which are components of the spindle motor of other embodiment of this invention after adhesion | attachment Sectional drawing which shows the suction plate 1 and the base 2 which are components of the spindle motor of other embodiment of this invention after adhesion | attachment Sectional drawing which shows the suction plate 1 and the base 2 which are components of the spindle motor of other embodiment of this invention after adhesion | attachment Sectional drawing which shows the suction plate 1 and the base 2 which are components of the spindle motor of other embodiment of this invention after adhesion | attachment Cross section of recording / reproducing device

Explanation of symbols

1 Suction plate 1a Suction plate side surface 1b Suction plate end surface (longitudinal direction)
1c End face of suction plate (short direction)
2 Base 3 Rotor magnet 4 Hub 4a Disk receiving surface 5 Stator core 6 Adhesive 7 Bearing device 10 Recording / reproducing device 11 Spindle motor 12 Disk 13 Magnetic head

Claims (10)

  A hub having a disk mounting portion, a rotor magnet fixed to the hub, a stator core wound with a coil facing the rotor magnet in a circumferential direction, a base to which the stator core is fixed, and a rotor magnet A spindle motor comprising a suction plate facing the end surface in the axial direction and fixed to the base, and having a wide portion on at least a part of a side surface of the suction plate.   A hub having a disk mounting portion, a rotor magnet fixed to the hub, a stator core wound with a coil facing the rotor magnet in a circumferential direction, a base to which the stator core is fixed, and a rotor magnet A spindle motor comprising a suction plate facing an end face in the axial direction and fixed to the base, wherein a side surface of the side surface of the suction plate has a shape portion whose width increases toward the base side.   The spindle motor according to claim 2, wherein a side surface of the suction plate has a tapered shape whose width increases toward the base side.   The spindle motor according to claim 2, wherein a side surface of the suction plate has a stepped shape having a flange on the base side.   3. The spindle motor according to claim 2, wherein a side surface of the suction plate is composed of a composite of a straight shape and a tapered shape.   A hub having a disk mounting portion, a rotor magnet fixed to the hub, a stator core wound with a coil facing the rotor magnet in a circumferential direction, a base to which the stator core is fixed, and a rotor magnet A spindle motor comprising: a suction plate facing the end surface in the axial direction and fixed to the base; and a side surface of the suction plate having a shape that widens toward the rotor magnet side.   The spindle motor according to claim 6, wherein a side surface of the suction plate has a tapered shape whose width increases toward the rotor magnet side.   The spindle motor according to claim 6, wherein a side surface of the suction plate has a stepped shape having a flange on the rotor magnet side.   The spindle motor according to claim 6, wherein a side surface of the suction plate is composed of a composite of a straight shape and a tapered shape. A recording / reproducing apparatus comprising the spindle motor according to claim 1.

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