JPH06253522A - Magnetic disc drive - Google Patents

Abstract

PURPOSE:To allow reduction of motor noise by forming a resin layer between respective core plates of a laminated core and surrounding the surface of the laminated core with an insulating material. CONSTITUTION:The magnetic disc drive comprises a hub 6 for mounting a magnetic disc on the outer peripheral surface thereof and driving the magnetic disc, a driving magnet 7 secured to the inner peripheral surface of the hub 6, and a stator core 12 wound around a coil 3 opposing to the driving magnet 7. The core 12 comprises a plurality of laminated core plates 2a each sandwiching a resin layer 12b and the surface of the laminated core 12 is surrounded by an insulating material 12a. This structure enhances bonding strength between respective core plates 2a and reduces motor noise because the laminated core 12 is integrated to enhance rigidity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive device.

[0002]

2. Description of the Related Art Conventionally, a magnetic disk drive device as shown in FIG. 9 is known. This magnetic disk drive device is a so-called bell-shaped bell with a fixed central axis, and in order to avoid complication of the drawing, only the right half of the center line is shown. In the figure, reference numeral 1 indicates a frame, and a through hole is formed in the center of the frame 1, and a groove having a constant width and extending along the circumference is formed on one surface. On the inner peripheral surface 1a of this groove, a laminated core 2 in which a plurality of cores 2a are laminated
Is fixed, and the coil 3 is wound around the laminated core 2. The center shaft 4 is fitted and fixed in the through hole, and the inner rings 5a, 5a of the bearings 5, 5 are provided on the outer periphery of the center shaft 4.
Are fitted and fixed. A hub 6 having a shape that covers the laminated core 2, the coil 3 and the like is fitted and fixed to the outer rings 5b and 5b of the bearings 5 and 5. A magnetic disk (not shown) is mounted on the outer peripheral surface of the hub 6, and a drive magnet 7 is fixed at a position on the inner periphery facing the laminated core 2. A terminal wire 8 is led out from the coil 3, and the terminal wire 8 is connected to a power supply means (not shown). By applying a predetermined drive voltage to the coil 3 from the power supply means, the hub 6 having the magnetic disk mounted thereon is rotated. Note that reference numeral 10 indicates a seal member.

By the way, in the above device, since the motor noise is relatively large, in order to address this problem, for example, in the device disclosed in Japanese Patent Laid-Open No. 3-230744, a floating material is provided and the drive magnet 7 is provided. The vibration from is not transmitted to the central axis 4.

[0004]

However, in the above-mentioned device, the noise was almost unchanged, which was insufficient as a countermeasure. Here, the present inventor has found that the main cause of motor noise is vibration from the laminated core 2 rather than vibration from the drive magnet 7. This is because the laminated core 2 has a low rigidity because the laminated core 2 is simply formed by laminating the cores 2a and caulking.

Therefore, an object of the present invention is to provide a magnetic disk drive device capable of reducing motor noise at a relatively low cost.

[0006]

In order to achieve the above object, a magnetic disk drive apparatus according to a first aspect of the present invention mounts and drives a magnetic disk on an outer peripheral surface of the hub, and a drive fixed to the inner peripheral surface of the hub. In a magnetic disk drive device comprising a magnet and a stator core having a coil wound opposite to the drive magnet, the core is composed of a plurality of laminated cores, and a resin is provided between core plates of the laminated core. A layer is formed and the surface of the laminated core is surrounded by an insulating material. In order to achieve the above object, the magnetic disk drive device of the second invention is characterized in that, in addition to the first means, an insulating resin is impregnated between the core plates of the laminated core. In order to achieve the above-mentioned object, the magnetic disk drive device of the third invention is characterized in that, in addition to the above-mentioned first means, the resin layer is made of a liquid thermosetting resin. In order to achieve the above object, the magnetic disk drive device of the fourth invention is characterized in that, in addition to the first means, the resin layer is made of a liquid thermoplastic resin. In order to achieve the above object, the magnetic disk drive device of the fifth invention is characterized in that, in addition to the above first means, a thermosetting adhesive is applied to at least one surface of each core plate of the laminated core. I am trying. In order to achieve the above object, the magnetic disk drive device of the sixth invention is characterized in that, in addition to the fifth means, the adhesive is a semi-cured powdery thermosetting adhesive. In order to achieve the above-mentioned object, a magnetic disk drive device of a seventh invention is characterized in that, in addition to the above-mentioned first means, a thermoplastic adhesive is applied to at least one surface of each core plate of the laminated core. There is. In order to achieve the above object, the magnetic disk drive device of an eighth invention is characterized in that, in addition to the seventh means, the adhesive is a semi-cured powdery thermoplastic adhesive.

[0007]

According to the magnetic disk drive device of the first to eighth means, the adhesive strength between the cores is increased, the laminated cores are integrated, and the rigidity is improved with a relatively simple structure. It

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of a magnetic disk drive according to a first embodiment of the present invention, in which the same parts as those described in the prior art are designated by the same reference numerals and the description thereof is omitted here. Is omitted. The magnetic disk drive device of the first embodiment is different from that of the prior art in that a resin layer 12b is formed between each core plate 2a and the surface of the whole laminated core is covered with an insulating material 1.
It is the point surrounded by 2a.

The manufacturing process of the laminated core 12 will be briefly described below with reference to FIG. First, as shown in FIG. 2A, a core material 11 made of, for example, silicon steel plate is punched into a desired core shape,
A core 2a having salient poles as shown in (b) is obtained.
Then, as shown in FIG. 2 (c), a plurality of cores 2a are stacked, and as shown in FIG. 2 (d), for example, a liquid thermosetting resin or a liquid thermoplastic resin is provided between the cores 2a. Is impregnated by, for example, a vacuum impregnation method and cured, and then the whole is subjected to an insulation coating treatment by, for example, powder coating and cured, so that an insulation coating 12a as shown in FIG. 2 (e) and FIG. A covered finished product will be obtained.

Here, as the liquid thermosetting resin,
Epoxy resin, urethane resin, silicon resin, acrylic resin, phenol resin, urea resin, and liquid thermoplastic resins include ethylene vinyl acetate type, polyamide type,
Polyester-based and rubber-based resins are suitable.

As the impregnation method, pressure impregnation, heat impregnation, solvent dilution method, etc. can be used instead of the vacuum impregnation method.

Further, instead of powder coating, insulators may be fitted from above and below the laminated core to obtain the insulating coating 12c as shown in FIG.

When a liquid thermosetting resin or liquid thermoplastic resin is impregnated, if a sufficient insulating film is formed also on the outer peripheral portion of the core, powder coating or insulating film treatment by an insulator may be omitted. It is possible.

Incidentally, the curing after the impregnation may be simultaneously performed in the curing step at the time of powder coating.

As described above, in the first embodiment, since the resin layer 12b is formed between the core plates 2a, the adhesive strength between the cores 2a is increased and the laminated core 12 is integrated. Therefore, the rigidity is improved, and hence the motor noise can be reduced.

The present inventor confirmed this through experiments.
The experimental results are shown in Table 1. Taking an epoxy resin as an example of the impregnating resin, bisphenol A type, made by Yuka Shell, 100 phr of Epicoat 801 and a curing agent of
Acid anhydride, made by Yuka Shell, 100 ph of YH-307
r, alkyl monoglycidyl ether as a reactive diluent, made by Yuka Shell, 10 phr of YED-1111,
As the curing accelerator, 1-isobutyl-2-methylimidazole and 1BM1-12 were used at 3 phr, respectively. The specifications of the device are 12V 4800 rpm.

[Table 1] As is clear from Table 1, when the resin is impregnated, noise is remarkably higher than that in the case where no resin is used or when a floating material is used (apparatus described in JP-A-3-230744). You can see that it is decreasing.

Moreover, the above structure does not use a floating material as in the prior art, is simple, and therefore can reduce the cost. Further, since the impregnation treatment can be performed after the core is annealed, iron loss can be reduced and therefore motor characteristics can be improved. Furthermore, since the laminated core 12 is subjected to the insulating film treatment on the entire surface thereof, the dustproof effect is also improved.

FIG. 4 is a side sectional view of a magnetic disk drive device showing a second embodiment of the present invention. The magnetic disk drive device of the second embodiment differs from that of the first embodiment in that a thermosetting adhesive layer 22b is formed between the core plates 2a.

The manufacturing process of the laminated core 22 will be briefly described below with reference to FIG. First, as shown in FIG. 5A, the core material 11 made of, for example, silicon steel sheet is preheated, and then, as shown in FIG. Agent 2
2b and then, as shown in FIG. 5 (c),
Heat to semi-cure. Next, the core material 11 having the semi-cured thermosetting adhesive 22b on one side is punched into a desired core shape as shown in FIG. 5 (d), and salient poles as shown in FIG. 5 (e). To obtain a core 22c having The core 22c has a semi-cured thermosetting adhesive 22b on one side. The core 22c is shown in FIG.
As shown in (f), a plurality of sheets are superposed and caulked,
Then, this laminated and crimped product is cured by heating, and the result is shown in FIG.
When a laminated core as shown in Fig. 5 is obtained, and then the whole is subjected to an insulating film treatment by, for example, powder coating and cured,
A finished product covered with the insulating coating 22a as shown in (h) and FIG. 4 is obtained.

Here, as the above-mentioned thermosetting adhesive, epoxy resin, urethane resin, silicon resin, phenol resin and urea resin are suitable. In addition, a lubricant may be added to these resins in order to facilitate the pressing work during crimping.

The thermosetting adhesive 22b may be applied on both sides, and the application range may be the entire surface or only a predetermined portion, and the application shape may be a strip shape, an island shape, or a non-repeating pattern shape. It may be. Further, the above thermosetting adhesive may be diluted with a solvent to facilitate application, or may be applied in a heated state without adding a solvent.

Instead of powder coating, insulators may be fitted from above and below the laminated core to obtain the insulating coating 22a.

Furthermore, heat curing of the laminated caulked product is
You may make it carry out simultaneously in the hardening process at the time of powder coating.

As described above, in the second embodiment, since the thermosetting adhesive layer 22b is formed between the core plates 2a, the adhesive strength between the cores 2a is increased and the laminated core 22 is By being integrated, the rigidity is improved, and therefore the motor noise can be reduced.

The present inventor confirmed this through experiments.
The experimental results are shown in Table 2. As an example of an epoxy resin as a thermosetting adhesive, bisphenol A type, oil-made shell, Epicoat 828 100 phr, hardener 1-isobutyl-2-methylimidazole, oil-made shell 1BM1-12 Is used for 4 phr, and aluminum stearate is used for 3 phr as a lubricant. The specifications of the device are 12V 4800 rpm.

[Table 2] Here, in the comparative example, the laminated crimped core (without the thermosetting adhesive layer 22b) was powder-coated. As is clear from Table 2, when the thermosetting adhesive is applied, the noise is remarkably reduced as compared with the comparative example.

Even with this structure, it is possible to obtain other effects similar to those of the first embodiment. That is, the conventional floating material is not used, and it is simple, and thus the cost can be reduced. Further, since the laminated core 22 is subjected to the insulating film treatment on the entire surface thereof, the dustproof effect is improved. Further, in addition to the effects of the first embodiment, since the thickness of the thermosetting adhesive 22b can be controlled at the time of application, it is possible to increase the thickness of the thermosetting adhesive 22b, thus reducing the eddy current. A new effect that the motor characteristics can be improved can be expected.

FIG. 6 is a side sectional view of a magnetic disk drive device showing a third embodiment of the present invention. The magnetic disk drive device of the third embodiment differs from that of the second embodiment in that the powdery thermosetting adhesive layer 32 is provided between the core plates 2a.
This is the point where b is scattered.

The manufacturing process of the laminated core 32 will be briefly described below with reference to FIG. First, as shown in FIG. 7A, a core material 11 made of, for example, silicon steel sheet is prepared, and then, as shown in FIG. Adhesive 32b is applied so that the powdery thermosetting adhesive 32b is scattered on the core material 11. Then, as shown in FIG. 7 (c), the powdery thermosetting adhesive is heated to be powdery thermosetting adhesive. 32b is attached on the core material 11. Next, the core material 11 having the powdery thermosetting adhesive 32b attached to one surface is punched into a desired core shape as shown in FIG.
A core 32c having salient poles as shown in FIG. This core 32c is a powdery thermosetting adhesive 32 attached to one side.
b. Then, as shown in FIG. 7F, a plurality of the cores 32c are superposed and caulked, and then the laminated caulked product is heat-cured to obtain the core 32c.
A laminated core as shown in (g) is obtained, after which
For example, if you apply an insulating film treatment by powder coating and cure it,
A finished product covered with the insulating coating 32a as shown in FIGS. 7 (h) and 6 is obtained.

Here, the powdery thermosetting adhesive 32b is used.
Is any one of epoxy resin, urethane resin, silicone resin, phenol resin, urea resin, imide resin
It is better to use two or more. The powder particle size is 150μ.
m or less is desirable. In addition, a lubricant may be added to these resins in order to facilitate the pressing work during crimping.

The powdery thermosetting adhesive 32b may be applied on both sides. Further, in order to facilitate application, the powdery thermosetting adhesive 32b may be diluted with a solvent, or may be applied in a heated state without adding a solvent.

Further, instead of powder coating, insulators may be fitted from above and below the laminated core to obtain the insulating coating 32a.

Furthermore, heat curing of the laminated caulked product is
You may make it carry out simultaneously in the hardening process at the time of powder coating.

As described above, in the third embodiment, since the powdery thermosetting adhesive layer 32b is scattered between the core plates 2a, the adhesive strength between the cores 2a increases.
Since the laminated core 22 is integrated, the rigidity is improved, and thus the motor noise can be reduced.

The present inventor confirmed this through experiments.
The experimental results are shown in Table 3. As an example of an epoxy resin as a powdery thermosetting adhesive, bisphenol A type,
Made by Yuka Shell, 100 phr Epicoat 828, 1-isobutyl-2-methylimidazole as a curing agent,
Made by Yuka Shell, 1 BM1-12 is used for 4 phr, inorganic filler is used for silica of 30 phr, and lubricant is used for aluminum stearate of 5 phr. The specifications of the device are 12V 4800 rpm.

[Table 3] Here, in the comparative example, the laminated caulked core (without the powdery thermosetting adhesive 32b) was powder-coated. Table 3
As is apparent from the above, when the powdery thermosetting adhesive 32b is applied, the noise is significantly reduced as compared with the comparative example.

Also, with this structure, it is possible to obtain other effects similar to those of the second embodiment. That is, the conventional floating material is not used, and it is simple, and thus the cost can be reduced. Further, since the laminated core 32 has the entire surface thereof subjected to the insulating film treatment, the dustproof effect is improved. Further, since the thickness of the powdery thermosetting adhesive 32b can be controlled at the time of application, the thickness of the thermosetting adhesive 22b can be increased, so that the eddy current is reduced and the motor characteristics can be improved. ing.

FIG. 8 is a side sectional view of a magnetic disk drive device according to the fourth embodiment of the present invention. The magnetic disk drive device of the fourth embodiment differs from that of the third embodiment in that a liquid or powdery thermoplastic adhesive layer 42b is formed between the core plates 2a.

The manufacturing process of the laminated core 42 will be briefly described below with reference to FIGS. 5 and 7. First, in the case of a thermoplastic adhesive, as shown in FIG. 5 (a), the core material 11 made of, for example, silicon steel plate is preheated, and then as shown in FIG. 5 (b). , The thermoplastic adhesive 42b is applied by the applying roller 13, while in the case of the powdery thermoplastic adhesive, the powdery thermoplastic adhesive 42 is applied by the nozzle 14 as shown in FIG. 7 (b).
b is applied and the powdery thermoplastic adhesive 42b is scattered on the core material 11. The subsequent steps are the same for both,
The core material 11 having the thermoplastic adhesive 42b on one surface is punched into a desired core shape as shown in FIG.
A core having salient poles as shown in FIG. 7 (e) is obtained.
This core has a thermoplastic adhesive 42b on one side. Then, as shown in FIG. 7 (f), a plurality of the cores are superposed and caulked, and then this laminated caulked product is heated to obtain a laminated core as shown in FIG. 7 (g). After that, if the whole is subjected to an insulating film treatment by, for example, powder coating and then cured, a finished product covered with an insulating film 42a as shown in FIGS. 7 (h) and 8 is obtained.

Here, as the thermoplastic adhesive 42b, ethylene vinyl acetate type, polyamide type, polyester type, rubber type hot melt or the like can be used. Further, a lubricant may be added to these in order to facilitate the pressing work during crimping.

The application of the thermoplastic adhesive 42b may be performed on both sides, and the application range may be the entire surface or only a predetermined portion, and the application shape may be a strip shape, an island shape, or a non-repeating pattern shape. May be.

Instead of powder coating, insulators may be fitted from above and below the laminated core to obtain the insulating coating 42a.

Furthermore, the heat curing of the laminated caulked product is
You may make it carry out simultaneously in the hardening process at the time of powder coating.

As described above, in the fourth embodiment, since the thermoplastic adhesive layer 42b is formed between the core plates 2a, the adhesive strength between the cores 2a is increased and the laminated core 42 is integrated. It is possible to reduce the motor noise by improving the rigidity.

The present inventor confirmed this through experiments.
The experimental results are shown in Table 4. As an example of hot melt as a thermoplastic adhesive, polyamide-based, Sony Chemical's Hyper Hot Melt 274 is used as a lubricant.
Aluminum stearate is used respectively. The specifications of the device are 12V 4800 rpm.

[Table 4] Here, the comparative example is a laminated crimped core (thermoplastic adhesive 4
2b is not applied) and powder is applied. As is clear from Table 4, when the thermoplastic adhesive 42b is applied, the noise is significantly reduced as compared with the comparative example.

Also, with this structure, it is possible to obtain other effects similar to those of the second embodiment. That is, the conventional floating material is not used, and it is simple, and thus the cost can be reduced. Further, the laminated core 42 has an insulating film treatment applied to the entire surface thereof, so that the dustproof effect is improved. Further, since the thickness of the thermoplastic adhesive 42b can be controlled at the time of application, the thickness of the thermoplastic adhesive 42b can be increased, so that the eddy current is reduced and the motor characteristics can be improved.

The invention made by the present inventor has been specifically described based on the embodiments, but the invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say, for example, in each of the above-mentioned embodiments, the application example to the central axis fixed type magnetic disk drive device is described, but it is also applicable to the central axis rotation type magnetic disk drive device. Of course, it is applicable.

[0046]

As described above, according to the magnetic disk drive device of the present invention, the adhesive strength between the cores is increased, so that the laminated cores are integrated and the rigidity is improved.
Therefore, motor noise can be reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view of a magnetic disk drive device showing a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a manufacturing process of the laminated core in FIG.

FIG. 3 is a side sectional view showing a laminated core having an insulating coating formed by an insulator.

FIG. 4 is a side sectional view of a magnetic disk drive device showing a second embodiment of the present invention.

FIG. 5 is a diagram for explaining a manufacturing process of the laminated core in FIG.

FIG. 6 is a side sectional view of a magnetic disk drive device showing a third embodiment of the present invention.

FIG. 7 is a diagram for explaining a manufacturing process of the laminated core in FIG.

FIG. 8 is a side sectional view of a magnetic disk drive device showing a fourth embodiment of the present invention.

FIG. 9 is a side sectional view of a conventional magnetic disk drive device.

[Explanation of symbols]

 2a each core 3 coil 6 hub 7 drive magnet 12, 22, 32, 42 laminated core 12a, 12c, 22a, 32a, 42a insulating material 12b, 22b, 32b, 42b resin layer

Claims (8)

[Claims] 1. A hub for mounting and driving a magnetic disk on an outer peripheral surface thereof, a drive magnet fixed to an inner peripheral surface of the hub, and a stator core having a coil wound opposite to the drive magnet. In the magnetic disk drive, the core is composed of a plurality of laminated cores, a resin layer is formed between core plates of the laminated core, and the surface of the laminated core is surrounded by an insulating material. Magnetic disk drive device. 2. The magnetic disk drive device according to claim 1, wherein an insulating resin is impregnated between the core plates of the laminated core. 3. The magnetic disk drive device according to claim 1, wherein the resin layer is made of a liquid thermosetting resin. 4. The magnetic disk drive device according to claim 1, wherein the resin layer is made of a liquid thermoplastic resin. 5. The magnetic disk drive device according to claim 1, wherein a thermosetting adhesive is applied to at least one surface of each core plate of the laminated core. 6. The magnetic disk drive device according to claim 5, wherein the adhesive is a semi-cured powdery thermosetting adhesive. 7. The magnetic disk drive device according to claim 1, wherein a thermoplastic adhesive is applied to at least one surface of each core plate of the laminated core. 8. The magnetic disk drive device according to claim 7, wherein the adhesive is a semi-cured powdery thermoplastic adhesive.