JP2002315254A - Disk drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk drive which is designed smaller and thinner than that of a prior art, assures superior processing ability and productivity and does not generate vibration and operation noise. SOLUTION: This disk drive comprises a base member 1, a rotor hub 4 which relatively rotates freely with respect to the base member 1 and loads a disk, a rotor magnet 5 loaded to the rotor hub 4, a stator core 61 arranged facing the rotor magnet 5 and a stator 6 having a stator coil 62. A through-hole 11 for accommodating the stator coil 62 is formed on the base member 1 formed by a press molding process, the bottom surface of the through-hole 11 is sealed by outsert molding and a rib 15 is formed on the base member 1. Here, in order to acquire the amount of winding of the stator coil 62, while the device is formed in further thinner shape, it is preferable to further provide a stator step 16 at the base member 1 with the outsert molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a device for driving a disk-type recording medium such as a hard disk, and more particularly to a small and thin disk drive.

[0002]

2. Description of the Related Art In recent years, disk drives have been mounted on various devices including personal computers. With the recent reduction in size and weight of these devices, there is a strong demand for smaller and lighter disk drives, especially thinner disk drives.

Therefore, for example, a through hole for accommodating a stator coil and a stator step for mounting a stator core are provided on a base member formed by, for example, aluminum die-casting by press working or coining, and winding of the stator coil is performed. Attempts have been made to reduce the thickness of the device while ensuring a sufficient dose.

[0004]

However, when an extremely thin member having a thickness of about 0.4 mm or less is formed by die casting, a hollow portion is formed in the member because the molten metal does not flow smoothly in the mold. . For this reason, it is difficult to form such a thin member by die casting. On the other hand, after forming a member with a predetermined thickness by die casting, it is also conceivable to perform cutting to reduce the thickness of the member, but when the member is cut to a thickness of 0.4 mm or less, deformation of the member is inevitable. As such, such a processing method is not practical.

Conventionally, the through-hole for accommodating the stator coil is merely sealed with a seal member, so that the rigidity of the base member is reduced, and the vibration of the stator due to magnetic induction and the noise caused by the vibration are generated. Was.

Further, in order to form a stator step by pressing, the pressing itself is difficult, and in addition, the processing cost is high and the yield is low.

The present invention has been made in view of such a conventional problem, and is smaller and thinner than conventional disk drive devices, has excellent workability and productivity, and has a high vibration resistance. It is an object of the present invention to provide a disk drive device free from noise and noise.

[0008]

According to the present invention, a base member, a rotor hub rotatable relative to the base member and having a disk mounted thereon, a rotor magnet mounted on the rotor hub, In a disk drive device provided with a stator having a stator core and a stator coil disposed opposite to a rotor magnet, the base member is formed by press molding and has a through hole for accommodating the stator coil. A disk drive device having a hole, wherein a bottom surface of the through hole is sealed by outsert molding, and a rib is formed on the base member is provided.

Here, from the viewpoint of securing the winding amount of the stator coil while further reducing the thickness of the device, it is preferable to further provide a stator step on the base member by outsert molding.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a disk drive according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing one embodiment of the disk drive device of the present invention. 1 is a base plate (base member)
1, a shaft member 2 fixed to the base plate 1 from the back side by screws 13, a pair of bearings 3 (3a, 3b) attached to the shaft member 2 at a predetermined interval, and the pair of bearings 3 The rotor includes a rotor hub 4 rotatably supported by the shaft member 2, an annular rotor magnet 5 mounted on an outer periphery of a lower end of the rotor hub 4, and a stator 6 disposed to face the rotor magnet 5. A groove D in which the bottom surface of the through hole 11 is sealed with a resin R is formed in the base plate 1, and the lower end of the stator coil 62 is accommodated in the groove D. Although not shown in this figure, resin ribs 15 (shown in FIG. 2) are formed between the grooves to compensate for the reduced rigidity of the base plate 1 due to the formation of the through holes 11. .

First, the base plate, which is a feature of the present invention, will be described. FIG. 2 is a perspective view of the base plate before and after outsert molding. In the base plate 1 before outsert molding, a substantially rectangular through hole 11 radially formed around the mounting hole 14 of the shaft member 2 and a rib 15 and a stator step 16 by outsert molding described later are formed. Holes 12 and 13 are formed. In the disk drive device of the present invention, which aims at making the device thinner, the thickness of the base plate is much thinner than that of the conventional one (for example, about 0.3 mm). Efficient production with high accuracy. Specifically, the outer shape of the base plate is punched out of the thin plate by press molding, and at the same time, a hole is punched and formed at a predetermined position of the base plate, and a desired base plate is manufactured by performing a bending process and a drawing process as necessary. In this case, the base plate 1 is made of SUS3 in consideration of magnetic loss such as strength and magnetic flux leakage.
It is desirable to make it from a non-magnetic stainless steel material such as 16. The press molding conditions are not particularly limited and can be performed under conventionally known conditions. The shape and the number of the through holes 11 may be appropriately determined according to the shape of the stator coil 62 accommodated therein.

Then, the base plate 1 formed by press molding is further subjected to outsert molding to seal the bottom surface of the through hole 11 and, at the same time, to form the ribs 15 and, if necessary, the stator steps 16 on the base plate 1. Here, outsert molding refers to a method in which a base substrate is sandwiched between molds and necessary mechanisms and functional components are attached by one injection molding. FIG. 3 shows a specific forming method. FIG. 3 is a sectional view on a concentric circle centered on a shaft member mounting hole of the base plate.

First, the base plate 1 is divided into an upper mold M1 and a lower mold M.
2 (FIG. 3A). A hole 12 for forming a through-hole 11 and a rib 15 is formed in the base plate 1, and the bottom surface of the through-hole 11 formed in the base plate and a portion to be the rib 15 are formed as cavities in the upper die M <b> 1 and the lower die M <b> 2. ing. Then, the base plate 1 is sandwiched between the upper mold M1 and the lower mold M2, and heated to a predetermined temperature (FIG. 9B). Then, the resin R is poured into the cavity in the formed mold (FIG. 3C).
The resin that can be used here is not particularly limited as long as it is a thermoplastic resin, and may be a resin mixed with fibers or the like in order to increase the strength. In order to absorb the vibration generated in the stator, a resin that absorbs the vibration may be used. As the resin insertion gate method, a conventionally known method such as a multipoint pin gate, a side gate, a submarine gate, and a hot runner can be used. And mold M
After cooling the M1 and the resin R to solidify the resin R, the base plate 1 is removed from the mold (FIG. 4D). The removal taper of the resin molded product may be the same as that of a normal molded product.
A range of about ° is preferred.

The base plate thus manufactured (FIG. 2)
(A), a resin layer (not shown) is formed on one surface on the back surface side of the
Is sealed with a resin R to form a groove D. The deeper the groove D, the more the lower end of the stator coil 62 can be accommodated, while the rigidity of the pace plate 1 decreases. According to the results of experiments conducted by the present inventors using a base plate having a thickness of 0.3 mm, in order to balance the accommodation capacity of the stator coil with the rigidity of the base plate, the groove depth was set to 0.10 to 0.15 mm.
(Approximately 33% to 50% of the thickness of the base plate).

In FIG. 2A, the base plate 1
A rib 15 having a trapezoidal cross section is formed between the grooves D. Similarly to the above, in an experiment using a base plate having a thickness of 0.3 mm, it was found that if the height of the rib is at least about 1 mm from the bottom surface of the base plate, the rigidity of the base plate is practically acceptable. In addition, a stator step 16 is formed to secure the winding amount of the stator coil. Stator step 16
As the height is higher, the winding amount of the stator coil can be increased, but the device thickness becomes thicker. Therefore, the height of the stator step 16 may be appropriately determined from the relationship between the required winding amount and the device thickness.

Next, the assembly of a disk drive using such a base plate will be described. FIG. 4 shows an example of an exploded configuration diagram of the disk drive device of the present invention.

In FIG. 4, the stator 6 is a stator core 6
1 and a stator coil 62. Stator core 61
Has an annular base 611, nine legs (not shown) extending radially inward from the annular base at equal intervals in the circumferential direction, and a circumferentially extending portion formed at the tip of the leg. It is formed by laminating iron thin plates integrally formed with the salient poles 612. A wire is wound around the legs of the stator core 61 to form a stator coil 62.

The stator 6 is mounted on the stator step 16 having the annular base 611 of the stator core 61 so that the lower end of the stator coil 62 is inserted into the groove D formed in the base plate 1. Attach to base plate 1.

The rotor hub 4 shown in FIG. 4 is formed of a magnetic stainless steel such as SUS400 series, has a substantially cylindrical shape, and has a pair of bearings 3 fixedly held on its inner peripheral portion.
The rotor hub 4 is rotatably supported on the outer peripheral portion of the shaft member 2 via the bearing 3. Further, the outer peripheral surface of the rotor hub 4 is formed to have an outer diameter substantially equal to the inner diameter of a recording disk (not shown) such as a hard disk, and a substantially central portion is formed with a flange 41 for mounting the recording disk. . The rotor magnet 5 is fixedly held on the peripheral side surface of the flange 41.

Then, the bearing 3 fixed and held by the rotor hub 4 is press-fitted into the shaft member 2, and the rotor hub 4 is fixed to the shaft member 2 such that the rotor magnet 5 faces the stator core 61 inward and outward with a predetermined gap in the radial direction.

As described above, an inner rotor type drive device having a fixed shaft has been described as one embodiment of the disk drive device of the present invention. However, the present invention is not limited to this embodiment. Design changes and modifications without departing from the gist of the present invention, such as a rotor type, are also included in the technical scope of the present invention.

[0022]

According to the disk drive of the present invention, the base member is formed by press molding, so that the productivity is improved. Further, since the through-hole for accommodating the stator coil is formed in the base member, the device is small and thin. Was achieved. Furthermore, since the bottom surface of the through-hole is sealed by outsert molding and ribs are formed on the base member, the rigidity of the base member is reduced due to a reduction in size and thickness of the device, and vibration of the stator due to magnetic induction and the like are reduced. The generation of noise was prevented.

When the stator step is further provided on the base member by outsert molding, the winding amount of the stator coil can be secured while further reducing the thickness of the device.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a disk drive device of the present invention.

FIG. 2 is a perspective view of a base plate before and after outsert molding.

FIG. 3 is a process chart showing an example of outsert molding.

FIG. 4 is an exploded configuration diagram showing an example of the disk drive device of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 base plate (base member) 2 shaft member 3 bearing 4 rotor hub 5 rotor magnet 6 stator D groove R resin 11 through hole 15 rib 16 stator step 61 stator core 62 stator coil

Continued on the front page F term (reference) 5D109 BA02 BA15 BA18 BA20 5H605 AA04 AA05 AA08 BB05 BB19 CC02 CC04 CC05 DD03 DD09 EA19 EB10 FF01 GG12 GG18 5H621 AA04 HH01 JK05 JK08 JK13 JK17 JK19

Claims (2)

[Claims] A base member, a rotor hub rotatable relative to the base member, and on which a disk is mounted;
A disk drive device comprising: a rotor magnet mounted on the rotor hub; and a stator disposed to face the rotor magnet and having a stator core and a stator coil, wherein the base member is formed by press molding. A disk drive device having a through hole for accommodating a stator coil, wherein a bottom surface of the through hole is sealed by outsert molding and a rib is formed on the base member. . 2. The disk drive according to claim 1, wherein a stator step is formed on the base member by outsert molding.