JPH0313916Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a floppy disk that is precisely positioned using a metal core.

[Prior Art] Figures 1a and 1b are a plan view and a front view of a conventional floppy disk in which a core metal for driving is fixed to a soft magnetic sheet.

In Fig. 1, 1 is a magnetic sheet, and 2 is fixed to the magnetic sheet 1 at its flange portion 2a with an adhesive or the like, and is made of a material that is easy to process such as ferromagnetic metal, such as SUS430, _Hv 200 or less. It is a core metal. In this core metal 2, a positioning hole (hereinafter simply referred to as a hole) 3 is provided approximately at the center of an engaging portion 2c that is continuous from a flange portion 2a via a cylindrical portion 2b.
Further, on this engaging portion 2c, a positioning and driving hole (hereinafter simply referred to as hole) 4 is provided at a position offset from the hole 3. The above constitutes the floppy disk F.

Then, this floppy disk F is shown in Figure 1a.
As shown in the figure, it is housed in a cassette shell S, which is called a floppy disk cassette (hereinafter simply referred to as a cassette) C. Note that the hole 3 is burred.

FIG. 2 is a schematic diagram showing a floppy disk drive mechanism.

In FIG. 2, CH is a chassis, M is a drive motor attached to the chassis CH, A is a motor shaft of the drive motor that enters the hole 3, and P is a drive unit that enters the hole 4 for positioning and driving. It is fixed to the leaf spring L with a pin (hereinafter referred to as a drive pin). G is a magnet for attracting the core metal 2. Note that, as the drive motor M rotates, the motor shaft A, the leaf spring L, the drive pin P, and the magnet G all rotate.

Figures 3a, b, and c are explanatory diagrams for mounting and driving a floppy disk.

Note that only the core metal 2, motor shaft A, and drive pin P are illustrated.

Next, the operation of mounting and driving a floppy disk will be explained with reference to FIGS. 1 to 3.

When a cassette C containing a built-in floppy disk F is mounted on the drive mechanism by a loading mechanism (not shown in Fig. 2), the core bar 2 of the floppy disk F is attracted to the magnet G of the drive mechanism, and the hole is inserted into the cassette C. 3
is fitted with motor shaft A. However, the drive pin P does not necessarily fit into the hole 4, and is usually pressed against the core bar 2 at a position X, for example, on the circumference indicated by the dashed line in FIG. ing.

After that, when the drive motor M is rotated, the drive pin P rotates clockwise around the motor shaft A, and when it comes to the position of the hole 4, it is pressed by the leaf spring L and fits into the hole 4 (the third Figure b). When the drive motor M rotates further, the drive pin P comes into contact with the side 4a of the hole 4, so the floppy disk F moves to the right, and the motor shaft A rotates around the sides 3a and 3b of the hole 3.
At the same time, the drive pin P also touches the side 4a of the hole 4,
4b, position the floppy disk F, and rotate it clockwise (Fig. 3c).

[Problems to be solved by the invention] When the floppy disk F is installed and driven in the process described above, in the first step, the core metal 2 and the motor shaft A collide when the floppy disk F is installed. Then, in the next step, when positioning and driving the floppy disk F using the motor shaft A, the drive pin P, and the holes 3 and 4, the sides 3a and 3b of the hole 3 and the motor shaft A and the side 4a of the hole 4 are , 4b and the drive pin P collide,
When these impacts are repeated, the holes 3 and 4 of the core metal 2
becomes deformed and wears out. Therefore, the center of the core bar 2 shifts in proportion to the number of times the floppy disk F is attached and detached, and as a result, the center of the track of the magnetic sheet 1 shifts, making the floppy disk F unusable.

FIG. 4 is a graph of six samples in which the number of times the floppy disk was attached and detached and the deviation of the track center were measured.

As can be seen from the measurement results, an average deviation of the track center of 8.5μ (deviation value 5μ) occurs after 5000 wears, and an average deviation of 17.4μ (deviation value 9μ) occurs after 10000 times.

Therefore, it takes less than 10,000 cycles to exceed the track center deviation of 10μ (distance between tracks), which is a guideline for practical use. Therefore, the service life of the core metal 2 was shorter than that of the magnetic sheet 1.

Therefore, as a countermeasure against such deformation and wear, it is conceivable to form the core metal 2 from a hard material. However, as mentioned above, the core metal 2 has a flange part 2a and an engaging part 2c, and the flatness of both of these parts is very strictly required in order to determine the height of the floppy disk. When attempting to mold such a core bar 2 from a hard material, there were problems in that it was not only difficult to process, but also that flatness could not be easily obtained. In addition, the mold wear was severe, which caused problems in terms of manufacturing costs.

[Means for solving the problems and their effects] The present invention was made in view of the above problems.The core metal is made of a material that is easy to process, and the core metal is plated with hard chrome. To provide a floppy disk with a long service life.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 5 is an enlarged sectional view of the core metal used in the floppy disk of this invention.

In Figure 5, 5 is hard chrome plating,
After processing the core metal 2, plating is applied. The rest of the structure is the same as that of the core bar 2 shown in FIG. 1, and the core bar 2 is formed of a flange part 2a for fixing the magnetic sheet 1, an engaging part 2c provided with holes 3 and 4, and a cylindrical part 2b. ing.

FIG. 6 is a graph showing the number of times the floppy disk was mounted and the deviation of the track center of nine samples using the core metal shown in FIG. 5.

Note that the measurement was made using the core metal 2 to which the hard chrome plating 5 had a thickness of 5μ.

As can be seen from these measurement results, in the floppy disk of this invention, the deviation of the track center is as small as 2.5μ on average (deviation value 1.2μ) after 5,000 times of mounting, and even after 30,000 times of mounting, the deviation of the track center is small on average.
Only 4.4μ of track center deviation (deviation of 1.1μ) occurred, and the service life was significantly extended compared to conventional products.

In the above embodiments, the holes 3 are burred, but the same effect can be obtained even when positioning is performed using only the holes 3 without burring.

[Effects of the invention] As explained above, the floppy disk of this invention uses hard chrome plating on the core metal, so the core metal does not need to be molded with a particularly hard material when the floppy disk is installed. This reduces the deviation of the track center due to deformation and wear, and dramatically increases the number of times it can be worn. Therefore, the service life of the floppy disk is improved, and there is also the advantage that it is not difficult to obtain flatness of the flange portion and the engaging portion during molding of the core metal.

[Brief explanation of drawings]

Figures 1a and b are a plan view and a front view of a conventional floppy disk, Figure 2 is a schematic diagram showing a floppy disk drive device, and Figures 3a, b, and c are floppy disk attachments, An explanatory diagram of the drive. Fig. 4 is a graph measuring the number of times a conventional floppy disk is mounted and the deviation of the track center. Fig. 5 is a cross-sectional view of the core metal used in the floppy disk of this invention. Fig. 6 is This is a graph showing the number of times the floppy disk of this invention was attached and the deviation of the track center. In the figure, 1 is a magnetic sheet, 2 is a core metal, 2a is a flange part, 2b is a cylindrical part, 2c is an engaging part, 3 and 4 are holes, 5 is hard chrome plating, F is a floppy disk, and S is a cassette. Ciel, C is for cassette, M
is the drive motor, A is the motor shaft, P is the drive pin, G
indicates a magnet.

Claims (1)

[Claims for Utility Model Registration] A floppy disk that includes a magnetic sheet with a metal core in the center, comprising: a flange portion that fixes the magnetic sheet; an engaging portion that engages with a turntable of a disk drive device; It is formed from a cylindrical part connecting the flange part and the engaging part, and the engaging part further includes:
A positioning hole for positioning and engaging the motor shaft of the disk drive device with two positioning sides approximately in the center, and a positioning hole for positioning and engaging the drive pin of the disk drive device at a position offset from the positioning hole with two positioning sides. Hard chrome plating is applied to the core metal molded so as to form a mating drive hole, thereby improving the durability of each of the positioning sides and maintaining positioning accuracy with respect to the turntable. A floppy disc that is characterized by: