JPH0616332B2 - Flexible magnetic disk - Google Patents

Description

The present invention relates to the structure of a flexible magnetic disk.

[Conventional technology]

1A and 1B are plan views of a front surface and a back surface of a conventional disk cassette incorporating a flexible magnetic disk. The magnetic disk cassette 1 has a flat case 2 in which a magnetic disk 3 is rotatably housed, and is used as a recording medium of an electronic camera having a microcomputer, a CCD and the like built therein. The magnetic disk 3 has a center core 4 for mounting in a disk drive device, and the center core 4 is magnetically coupled to a drive shaft of the disk drive device through center holes 7 and 8 formed on the front and back of the case 2. . Therefore, a ring-shaped permalloy 9 attracted to the magnet of the drive device is attached to the back side of the center core 4, and a spindle hole 5 into which the spindle of the disk drive device is inserted is formed in the center of the center core 4. There is.

A pressing pad insertion opening 11 is provided on the case 2 and the front and back surfaces
Further, a head insertion opening 12 is formed, and a slide type shutter 10 for closing the openings 11 and 12 is attached to the case 2 when the cassette is not used.

The center core 4 is made of resin, and the spindle hole 5 is defined by a V-shaped tapered surface 14 and a thin plate-shaped spring surface 15. The spindle inserted into the hole 5 is pressed against the tapered surface 14 by the spring surface 15, whereby centering (centering) of the disk is performed.

[Problems to be Solved by the Invention]

The entire center core 4 used in the above-mentioned conventional technology is
Since it is formed by resin molding, the dimension between the taper surface 14 and the spring surface 15 during molding tends to vary, and since it changes over time, disc misalignment occurs and disc rotation is eccentric. . Further, since the spring surface 15 is made of resin, due to variations in dimensions during molding and changes with time,
It was difficult to apply and maintain an appropriate spring force.

Japanese Unexamined Patent Publication (Kokai) No. 58-224479 discloses the use of a metal leaf spring as an elastic member for disc centering. However, when the leaf spring is embedded in a resin hub, it is parallel to the disc rotating surface. If the accuracy is low, the disk is fixed to be tilted with respect to the spindle, and surface wobbling of the disk occurs, which makes stable recording and reproduction difficult.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a center core structure for a disk, which has extremely high accuracy in holding the disk perpendicularly to the spindle rotation axis and centering accuracy.

[Means for Solving the Problems]

The flexible magnetic disk according to the present invention is a flexible disk 3.
A metal core member 18 having a mounting surface on which the disk 8 is mounted and a central hole 19 into which a spindle 40 provided in the disk drive device is inserted, and provided around the central hole 19 of the core member 18. , The ring member 25 for positioning the flexible disk 38 with respect to the spindle 40, and a pair of protrusions 36a and 36b at both ends.
Leaf spring 3 for pressing the spindle 40 inserted into the inner peripheral surface (taber surface 20a, 20b) of the ring member 25.
5 and a spring bearing surface 21 provided on the core member 18
and a cap member 39 for fixing the leaf spring 35 by sandwiching the protrusions 36a and 36b from above while the lower side edge of the protrusion of the leaf spring 35 is supported by a and 21b. And

According to this structure, since the metal core member 18 is used, the shape of the hole through which the spindle is inserted, the change over time and wear are small, and the spring receiving surface provided on the core member 18 causes the leaf spring for centering. Since the plate 35 is supported and fixed by the cap member 39, the parallel accuracy of the leaf spring 35 with respect to the disk rotation surface is high, and therefore, the right angle holding accuracy and centering accuracy of the disk with respect to the spindle rotation axis are high, and stable recording / reproducing is possible. Becomes

〔Example〕

 The configuration of the present invention will be described below with reference to examples.

FIG. 2 is a plan view of a sheet metal core member 18 forming the main part of the center core of a flexible magnetic disk according to the present invention.
The drawing is a sectional view taken along the line AA of FIG. This core member 18
Is a soft iron plate or the like punched into a ring shape, and has a pair of tapered surfaces 20a, 20a around the center hole 19 thereof.
b and a pair of spring bearing surfaces 21a and 21b are formed. The spring bearing surfaces 21a and 21b are orthogonal to the AA line.
The core member 18 also functions as a yoke material that is attracted to the chucking magnet of the disk drive device. Therefore, the permalloy ring 9 as shown in FIG. 1B becomes unnecessary.

As shown in FIG. 2, the shape of the core member 18 is line-symmetrical with respect to the line AA, and a bent portion 22 is formed on the line AA around the inner periphery of the center hole 19. This bent portion 22 is
The rotation detector of the disk drive device faces the rotation detector, and the rotation detector detects the leakage magnetic flux of the chucking magnet to obtain a pulse indicating the rotation phase of the disk. Since this bent portion is provided on the line AA, it is easy in design to balance the rotational dynamic balance of the core member 18 itself. For example, as shown in FIG. By providing the notch 23 on the −A line, it is possible to obtain the core member 18 having a dynamic balance.

As shown in the plan view of FIG. 4 and the cross section taken along the line BB of FIG. 5, the ring member 25 serving as the core material of the disk outsert-molds the resin around the center hole 19 of the core member 18. Mounted by. The diameter of the outer peripheral surface 26 of this ring member matches the inner diameter of the center hole of the magnetic disk, and the disk is positioned by this outer peripheral surface 26 to allow the core member 18 to be positioned.
Fixed to. At the same time as the outsert molding of the ring member 25, a ring-shaped rib 27 for welding the disk is formed on the lower surface of the outer peripheral portion of the core member 18. This rib 27
In order to outsert the core member 18 into the core member 18, a plurality of holes 28 and grooves 29 are formed on the outer periphery of the core member 18.

The center hole 30 of the ring member 25 is generally smaller than the center hole 19 of the core member 18 as shown in FIG. 4, but only the tapered surfaces 20a and 20b of the core member 18 are
As shown in FIG. 6 which is a partial cross-sectional view taken along the line CC of FIG. 4, it projects from the inner peripheral surface 31 of the center hole 30 of the ring member 25. As a result, the periphery of the spindle comes into contact with the tapered surfaces 20a and 20b. The inner peripheral surface 32 of the center hole 30 of the ring member 25 below the core member 18 is tapered surface 20a or 2 as shown in FIG.
It is flush with 0b, which prevents the spindle from directly hitting the edge of the tapered surface 20a, facilitates insertion of the spindle, and prevents the spindle from being scraped and the centering accuracy being lowered.

Slits 34a, 34b are formed in the ring-shaped member 25 at the portions corresponding to the spring receiving surfaces 21a, 21b of the core member 18, and the leaf springs 35 shown in FIG. 7 are inserted therein. The spring bearing surfaces 21a and 21b of the core member 18 are located substantially in the center of the width of the slits 34a and 34b, and when the leaf spring 35 is inserted, the spring bearing surfaces 21a and 21b are inserted.
The leaf spring 35 is supported by the radial direction. Further, protrusions 36a and 36b are formed on both sides of the leaf spring 35, and the leaf spring 35 is axially supported by the protrusions hanging on the core member 18 in the slits 34a and 34b.

As described above, the leaf spring 35 is attached to the slits 34a and 34b, and the magnetic disk 38 is attached to the outer peripheral surface 26 of the ring member 25 on the upper surface of the core member 18 as shown in the sectional view of FIG. A magnetic disk having a center core is completed by fitting the cap member 39 shown in the perspective view of FIG. 8 and the sectional view of FIG. 9 onto the disk 38, and then high-frequency welding the cap member 39 and the ring member 27. To do.

In this state, as shown in FIG. 11 (cross section along the leaf spring 35), the slits 34a and 34b into which the convex portions 36a and 36b at both ends of the leaf spring 35 are inserted are covered by the cap member 39, and thus the leaf spring is formed. 35 does not fall out.

FIG. 12 is a partial detailed view showing a state in which the spindle 40 of the disc drive device is inserted into the hole of the center core of the disc. As shown in FIG. 12, the spindle 40 causes the leaf springs 35 to be formed on both the tapered surfaces 20a and 20b of the core member 18.
The disc is positioned (centered) by being pressed by. Therefore, highly accurate centering according to the dimensional accuracy of the punched sheet metal core member 18 is performed without variation. Further, since the positional relationship between the tapered surfaces 20a and 20b and the leaf spring 35 is defined by the spring receiving surfaces 21a and 21b formed on the core member 18, a constant spring pressing force without variation and temporal change can be obtained. Stable and highly accurate centering can be performed.

〔The invention's effect〕

As described above, according to the present invention, since the metal core member 18 is used as the center core of the flexible magnetic disk, the shape of the hole through which the spindle is inserted is less likely to change with time and is worn away. Since the leaf spring 35 for centering is supported by the spring receiving surface provided on the and fixed by the cap member 39, the precision of parallelism of the leaf spring 35 with respect to the disc rotation surface is high, and therefore the precision of holding the disc at right angles with respect to the spindle rotation axis and High centering accuracy enables stable recording and reproduction.

[Brief description of drawings]

FIGS. 1A and 1B are front and back views of a conventional magnetic disk cassette, FIG. 2 is a plan view of a sheet metal core member that forms a main part of a flexible magnetic disk according to the present invention, and FIG. 2 is a cross-sectional view taken along the line AA in FIG. 2, FIG. 4 is a plan view showing a state in which a ring member as a disk core material is outsert-molded to the core member in FIG. 2, and FIG. 5 is a line BB in FIG. Cross section,
6 is a partial sectional view taken along the line CC of FIG. 4, FIG. 7 is a plan view of the leaf spring, and FIG. 8 is a perspective view of a cap member mounted together with the magnetic disk at the center of the phosphorus member of FIG. Fig. 9 is a vertical sectional view of Fig. 8, Fig. 10 is a sectional view of the assembled disk center core, Fig. 11 is a sectional view of the center core along a leaf spring, and Fig. 12 is a spindle. It is a partial detailed view of the state inserted in the center core. In addition, in the code | symbol used in drawing, 18 ... Core member 19 ... Center hole 20a, 20b ... Tapered surface 21a, 21b ... Spring receiving surface 25 ... Ring member 34a, 34b ... Slit 35 ... Leaf spring 38 ... magnetic disk 39 ... cap member 40 ... spindle.

Claims (1)

[Claims] 1. A metal core member having a mounting surface on which a flexible disk is mounted and a central hole into which a spindle provided in a disk drive is inserted, and a periphery of the central hole of the core member. And a ring member for positioning the flexible disk with respect to the spindle, and a pair of protrusions at both ends, and the spindle inserted into the ring member presses the inner peripheral surface of the ring member. A leaf spring and a cap member for fixing the leaf spring by sandwiching the protrusion from above with the lower side edge of the protrusion of the leaf spring supported by the spring receiving surface provided on the core member. A flexible magnetic disk characterized by being provided.