JP2913366B2 - Magnetic disk drive - Google Patents

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 such as a hard disk drive (HDD).

[0002]

2. Description of the Related Art Conventionally, a hub on which a magnetic disk is mounted, a rotor magnet mounted on the hub, a stator disposed opposite to the rotor magnet, and a clamp member for fixing the magnetic disk to the hub. And a magnetic disk comprising: a through hole into which a screw for fixing the clamp member to the hub is screwed and penetrated from the outer end surface to the inner end surface of the hub; and a shielding member for closing an opening in the inner end surface. Drives are known.

As shown in FIG. 2A, the through hole extends from the outer end surface 1a of the hub 1 toward the inner end surface 1b and has a female screw hole 1c into which the screw 2 is screwed. It is located coaxially with the screw hole portion 1c and extends from the inner end surface 1b to the outer end surface 1b.
The one provided with a hole 1d extending toward a (see, for example, Japanese Patent Application Laid-Open No. 4-54842). Alternatively, as shown in FIG. 3A, a female screw hole portion 1c into which a screw (not shown) is screwed from the outer end surface 1a to the inner end surface 1b of the hub 1 (for example, See JP-A-4-54852).

As shown in FIG. 2A, a magnetic disk 3 is fixed to the hub 1 via a clamp member 4. The clamp member 4 is fixed to the outer end surface 1a of the hub 1 by a screw 2 screwed into the female screw hole 1c. Although not shown, the magnetic disk drive shown in FIG. 3A also has a magnetic disk fixed by the same configuration as that of FIG. 2A.

[0005] By the way, when the surface treatment of the hub 1 (usually made of aluminum or the like) is performed, if the treatment liquid does not sufficiently penetrate into the details of the female screw portion, an untreated portion is formed in the through hole. It is penetrated to cause rust. On the other hand, after assembling, the openings on the inner end face 1c side are closed by the shielding members 6, 7 in order to secure the cleanness in the disk chamber 5.
Is closed by

[0006]

By the way, in the magnetic disk drive configured as described above, for example,
In the case where the female screw hole portion 1c and the hole portion 1d are provided, a boundary portion thereof is provided, and when only the female screw hole portion 1c is formed, an opening portion of the inner end surface 1b thereof is provided in FIG. , FIG.
As shown in (B), burrs 8 are formed during formation,
There was a problem that the processing of this burr 8 was very troublesome.

The present invention has been made in view of the above circumstances, and provides a magnetic disk drive capable of preventing generation of burrs, eliminating post-processing, and easily processing through holes. With the goal.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a hub on which a magnetic disk is mounted, a rotor magnet mounted on the hub, and a rotor magnet opposed to the rotor magnet. , A clamp member for fixing the magnetic disk to the hub, a through hole into which a screw for fixing the clamp member to the hub is screwed, and an opening in the inner end surface. A through hole extending from the outer end surface of the hub toward the inner end surface of the hub, the female screw hole portion engaging with the screw, and the female screw hole portion. And a hole positioned coaxially, and the inner diameter of the hole is set larger than the root diameter of the female screw hole,
The gist is that a tapered surface is formed at a boundary portion between the female screw hole and the hole.

[0009]

According to the first aspect of the present invention, a rotor magnet is mounted on a hub on which a magnetic disk is mounted, and a stator is disposed to face the rotor magnet.
The magnetic disk is fixed to the hub via the clamp member,
A screw for fixing the clamp member to the hub is screwed into a female screw hole extending from the outer end face toward the inner end face, and is located coaxially with the screw hole and has an inner diameter smaller than the root diameter of the female screw hole. The opening of the hole which is set large and extends from the inner end surface toward the outer end surface is closed by the shielding member, and the tapered surface is formed at the boundary between the female screw hole and the hole.

[0010]

Next, an embodiment of the magnetic disk drive of the present invention will be described with reference to FIG.

In FIG. 1A, a magnetic disk drive 11 includes a base 12 having a disk-shaped flange 12a,
A fixed shaft 13 fixed to the center of the base 12;
2, a hub 16 rotatably mounted on the protruding end of the fixed shaft 13 via bearings 15, 15, and a center opening 16 a of the hub 16. , A substantially cylindrical yoke 18 fixed to the hub 16, and the rotor magnet 1 fixed to the inner peripheral surface of the yoke 18 so as to face the stator 14.
9 is provided.

The hub 16 is formed with a through hole 20 penetrating from the outer end face 16b to the inner end face 16c. A magnetic disk is fixed to a peripheral end surface 16 d of the hub 16 via a clamp member 22. The clamp member 22 is fixed to the outer end surface 16b via a screw 23.

The through hole 20 extends from the outer end surface 16b to the inner end surface 1b.
A female screw hole 20a extending toward 6c and screwed with the screw 23; and an inner end face 1 coaxially located with the female screw hole 20a.
A hole 20b extending from 6c toward the outer end face 16b;
A tapered surface 20c is formed at the boundary between the female screw hole 20a and the hole 20b. Further, the angle θ of the tapered surface 20c is set so that the hole 20
It opens at an angle of 15 ° or more and 45 ° or less toward the b side.

As shown in FIG. 1B, the inner diameter D1 of the hole 20b is set to be larger than the root diameter D2 of the female screw hole 20a. The hole 20b has a tapered surface 2
0c together with blanking such as casting and sintering ,
It is formed at the same time when the general shape is formed by casting or sintering , and the female screw hole 20a is formed thereafter. At this time, no burr is generated at the end of the female screw hole 20a on the inner end surface 16c side due to the tapered surface 20c having an expanded shape. Further, an opening located on the inner end surface 16c of the hole 20b is thus closed to the shielding member 24.

In the above configuration, the magnetic disk drive 11 fixes the fixed shaft 13 to the base 12 and
Stator 1 in which coil 14a is wound around fitting protrusion 12b
The yoke 18 having the rotor magnet 19 is fixed to the hub 16, and the hole 20 b is closed by the shielding member 24.

Next, the hub 16 in which these are integrated is mounted on the fixed shaft 13 via the bearings 15, 15, the center opening 16 a is closed by the lid 17, and the motor body is assembled. The magnetic disk 21 is fixed to the hub 16 while the clamp member 21 is fixed to the hub 16 by screws 23.

In the magnetic disk drive 11 configured as described above, the magnetic disk 21 rotates integrally with the hub 16 by the current flowing through the coil 14a and the magnetic force of the rotor magnet 19.

[0018]

As described above, in the magnetic disk drive of the present invention, the through hole extends from the outer end surface of the hub toward the inner end surface, and the female screw hole portion into which the screw is screwed is provided. It is composed of a female screw hole and a hole located on the same axis, and the inner diameter of the hole is set to be larger than the root diameter of the female screw hole, and at the boundary between the female screw hole and the hole, Since the tapered surface is formed, generation of burrs can be prevented, post-processing can be omitted, and the processing of the through hole can be easily performed.

[Brief description of the drawings]

FIG. 1 shows a magnetic disk drive of the present invention, wherein (A)
1 is a longitudinal sectional view of a magnetic disk drive, and FIG. 1B is an enlarged sectional view of a main part.

2A and 2B show a conventional magnetic disk drive, wherein FIG. 2A is a longitudinal sectional view of a main part of the magnetic disk drive, and FIG. 2B is an enlarged sectional view of a through hole.

FIG. 3 shows another conventional magnetic disk drive,
(A) is a longitudinal sectional view of a main part of the magnetic disk drive,
(B) is an enlarged sectional view of the through hole.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Magnetic disk drive 14 ... Stator 16 ... Hub 16b ... Outer end face 16c ... Inner end face 19 ... Rotor magnet 20 ... Through hole 20a ... Female screw hole part 20b ... Hole part 20c ... Tapered surface 21 ... Magnetic disk 22 ... Clamp member 23 screw 24 shielding member

Claims (3)

(57) [Claims] 1. A hub on which a magnetic disk is mounted, a rotor magnet mounted on the hub, a stator disposed opposite the rotor magnet, and a stator for fixing the magnetic disk to the hub. A magnetic disk drive device comprising: a clamp member; a through hole into which a screw for fixing the clamp member to the hub is screwed; and a shielding member that shields an opening on the inner end surface. A female screw hole extending from the outer end surface of the hub toward the inner end surface and screwing with the screw; and a hole positioned coaxially with the female screw hole, and the inner diameter of the hole is A magnetic disk drive device characterized in that the diameter is set to be larger than the root diameter of the screw hole, and a tapered surface is formed at a boundary between the female screw hole and the hole. 2. The magnetic device according to claim 1, wherein the tapered surface is widened at an angle of 15 ° or more and 45 ° or less from the female screw hole toward the hole. Disk drive. The method according to claim 3, wherein said tapered surface and said hole portion, a magnetic disk drive according to claim 1, characterized in that it is formed simultaneously at the time of forming a more general shape casting or sintering.