JP2000276868A - Magnetic disk cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the good rotation of a magnetic disk by preventing the riding of a center core member over a hub hole even when a tapered part is provided in the inner peripheral corner part of the hub hole of a lower shell to prevent shaving caused by contact with the center core member. SOLUTION: This magnetic disk cartridge is constructed in such a manner that a flexible magnetic disk medium 4 fixed to the fixing flange 3a of a center core member 3 is rotatably housed in a case C joining upper and lower shells 1 and 2, a tapered part 15 is provided by chamfering off the inner corner part of a hub hole 2c opened in the bottom rough center of the lower shell 2, and a regulating rib 13 is disposed in the inner surface of the upper shell 1, in a position for regulating its movement by being abutted on the fixing flange 3a when the center core member 3 is inclined. Thus, the riding of a hub part 3b over the tapered part 15 of the hub hole 2c is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk-shaped magnetic disk medium having a center portion fixed to a center core member housed in a case, and rotating the magnetic disk medium to use the magnetic disk medium for magnetic recording and reproduction. The present invention relates to a disk cartridge, and more particularly, to a magnetic disk cartridge capable of reliably rotating a magnetic disk medium.

[0002]

2. Description of the Related Art In a magnetic disk cartridge, a disk-shaped flexible magnetic disk medium is rotatably accommodated in a case formed by joining upper and lower shell halves. Also,
A center core member is provided at a center portion of the magnetic disk medium. The center core member fixes and supports the magnetic disk medium to a fixing flange to define a center of rotation. The rotation driving force is transmitted while being engaged and held at the tip of the shaft.

In the magnetic disk cartridge, an opening for inserting a magnetic head and a shutter member for opening and closing the opening are provided in a case, and a hub hole for exposing a hub portion of a center core member is opened on a bottom surface. In rotating the magnetic disk medium, the center pin of the spindle shaft is inserted and engaged with the center hole of the hub of the center core member, but the drive pin hole is opened at a position shifted from the center position. However, at first, the positions of the drive pins do not match, and the drive pins engage with the drive pin holes to perform chucking during one rotation of the spindle shaft.

When a magnetic disk cartridge as described above is loaded into a drive device and the center core member is engaged and held by a spindle shaft, the center core member is inclined until the drive pin engages with the drive pin hole. In addition, the center core member may be inclined when the magnetic disk cartridge is attached to or detached from the drive device, and the hub portion rides on the inner corner of the hub hole on the bottom surface of the case and becomes unusable. There is fear.

[0005] In addition, such a magnetic disk cartridge is required to have a large capacity, and in a magnetic disk cartridge with an increased recording capacity, the rotational speed is increased to increase the data transfer speed. Become. With the increase in the recording capacity of magnetic disk media,
The high-speed rotating magnetic disk medium and the height of the recording / reproducing magnetic head are originally strictly maintained in an appropriate positional relationship, whereby the desired recording / reproducing performance can be secured.

However, in the case of a flexible magnetic disk medium, it is difficult to maintain a strict positional relationship with the above-mentioned magnetic head due to the occurrence of surface runout during rotation. Even when the position of the magnetic disk medium is shifted with respect to the head, the width of the penetration performance that follows the position is narrowed. Therefore, it is preferable that the magnetic disk medium bend easily to improve the followability in relation to the magnetic head.

[0007] From the above point, for example, the width of the fixing flange of the center core member is narrowed to reduce the joining range with the magnetic disk medium, and the inner peripheral portion of the magnetic disk medium is received by joining with the center core member. Regulations are reduced, and the magnetic disk medium is easily bent to improve the penetration performance.

On the other hand, during use of the magnetic disk cartridge, dust that has entered from the outside gets stuck between the recording / reproducing head and the magnetic disk medium, causing problems such as damage to the recording surface and dropout. In the case of a magnetic disk medium having a high recording density, the influence of dust is a serious problem.

In view of the above, in order to prevent dust from entering the magnetic disk cartridge in use from the hub hole on the bottom surface, a shield such as rubber is provided around the hub hole on the bottom surface of the magnetic disk cartridge loaded in the drive device. Pressing members has been performed.

[0010]

When the shielding member is pressed against the bottom surface of the case of the magnetic disk cartridge as described above, the bottom surface of the shell undergoes deformation such that the internal space is reduced, and the inner peripheral angle between the center core member and the hub hole is reduced. Shell shaving due to contact with the portion is likely to occur, and if the shaved powder adheres to the magnetic disk medium as dust, the above-described problem occurs.

In view of the above, in the present invention, in order to prevent the occurrence of the above-mentioned shell shaving, the inner corner of the hub hole of the lower shell is chamfered to provide a tapered portion, thereby avoiding contact with the center core member. However, the formation of the tapered portion makes it easy for the hub portion to run over when the center core member is inclined.

In particular, the riding phenomenon is remarkable in a high recording density magnetic disk cartridge in which the outer diameter of the fixing flange portion of the center core member is reduced, and improvement is demanded.

In view of the above, the present invention has been made in view of the above circumstances, and even if a tapered portion is provided at the inner peripheral corner portion of the hub hole, the center core member can be prevented from running on the hub hole and the magnetic disk can be smoothly rotated. Therefore, it is intended to provide a magnetic disk cartridge which ensures the above.

[0014]

A magnetic disk cartridge according to the present invention, which has solved the above-mentioned problems, has a disk-shaped flexible member fixed to a fixing flange of a center core member in a case formed by joining an upper shell and a lower shell. A magnetic disk cartridge rotatably accommodated therein, and a hub hole for exposing a disc-shaped hub portion of the center core member is opened at a substantially central portion of the bottom surface of the lower shell. In addition to providing a tapered portion by removing the corner portion in a chamfered shape, a regulating rib protruding from an inner surface of the upper shell and proximate to an outer peripheral portion of a fixing flange of the center core member is provided. When the center core member is inclined, the center core member comes into contact with the fixing flange and is disposed at a position where its movement is prevented.

Preferably, the center core member is a resin molded product as a whole, and a metal disk member is fixed to the bottom surface of the hub portion.

[0016]

According to the magnetic disk cartridge of the present invention as described above, the inside corner of the hub hole is removed in a chamfered shape to provide a tapered portion, thereby generating dust due to scraping due to contact with the center core member. And a regulating rib for abutting against the fixing flange when the center core member is inclined and restricting the movement thereof is protruded from the inner surface of the upper shell close to the outer peripheral portion of the fixing flange. Even if the diameter of the fixing flange is reduced, it is possible to effectively prevent the hub portion of the center core member from climbing into the hub hole and becoming unusable, thereby ensuring reliability in use.

Further, if the center core member is entirely formed of a resin molded product and a metal disk member is fixed to the bottom surface of the hub portion, the locking position accuracy with respect to the spindle shaft is improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 is an exploded perspective view of the upper and lower shells of the magnetic disk cartridge of the present embodiment, and FIG. 2 is a cross-sectional view showing a main configuration.

In the magnetic disk cartridge, a flat case C (hard case) is formed by joining an upper shell 1 and a lower shell 2 formed of a synthetic resin such as acrylonitrile-butadiene-styrene copolymer. A disk-shaped magnetic disk medium 4 whose central portion is attached to and held by the center core member 3 is rotatably accommodated in C. An upper liner 5 and a lower liner 6 are provided above and below the magnetic disk medium 4.

The magnetic disk medium 4 has a disk-shaped base made of a flexible polyester sheet or the like, and magnetic layers are formed on both sides of the disk-shaped base. An area 4a is set, and the inner and outer edges of this recording area are non-recording areas 4b.

The center core member 3 is formed by stamping a plate-shaped metal material made of a ferromagnetic material such as magnetic stainless steel into a predetermined shape and press-molding the same. A hub portion 3b in which the inner portion of the fixing flange 3a is provided in a concave shape, a center hole portion 3c is opened at a rotation center position of the hub portion 3b, and a drive pin hole portion 3d is opened further to the outer peripheral side. Have been. The spindle shaft 20 is inserted into the center hole 3c.
The center pin 21 (see FIG. 2) is inserted, the drive pin 22 is inserted and engaged in the drive pin hole 3d, the center of the bottom surface of the hub 3b abuts on the tip end surface of the spindle shaft 20, and the outer periphery is It is driven to rotate while being attracted by the magnet 23.

The upper shell 1 and the lower shell 2 have a substantially rectangular flat shape, and outer peripheral ribs 1a and 2a forming side walls are provided on the outer periphery, and the inner ribs 1b and 2b are substantially obliquely formed at corners. And a rectangular magnetic head insertion slot 1
0 and 11 are opened, and a circular hub hole 2c is opened in the center of the lower shell 2 in a size facing the hub 3b of the center core member 3.

On the inner surfaces of the upper shell 1 and the lower shell 2, an octagonal (or round) upper liner 5 and a lower liner 6 made of a nonwoven fabric or the like are adhered by ultrasonic welding or the like. The inner ribs 1b and 2b are formed outside the liners 5 and 6 along the shape thereof.

Although not shown, a shutter member slidable in the left-right direction in the figure is assembled to open and close the magnetic head insertion openings 10 and 11 of the case C.

The inner corner of the inner periphery of the hub hole 2c of the lower shell 2 is chamfered to form a tapered portion 15 (see FIG. 2). This taper part 1
Due to the formation of 5, even when the space inside the case C is deformed in a direction in which the space inside the case C is narrowed by the deformation when the shielding member 25 for preventing dust intrusion is pressed against the bottom surface of the outer periphery of the hub hole 2c when inserted into the drive device. , Fixing flange 3a for center core member 3
And the lower shell 2 can be prevented from being scraped.

At the center of the inner surface of the upper shell 1, there is provided an annular projection 12 projecting inward from the fixing flange 3a of the center core member 3.
Further outwardly, an annular regulating rib 13 protruding at a height lower than that of the annular projection 12 is provided near the outer periphery of the fixing flange 3a.

[0027] As shown in FIG.
The center core member 3 is fitted on the inner peripheral side of the fixing flange 3a to restrict the movement of the magnetic disk medium 4 in the radial direction. On the other hand, as shown in FIG. 3, when the center core member 3 is inclined, the restricting rib 13 comes into contact with the outer peripheral end of the fixing flange 3a to restrict the movement of the center core member 3, and the hub portion 3b Is the hub hole 2 of the lower shell 2
It is disposed at a position where it is prevented from riding on the tapered portion 15 of FIG.

According to the magnetic disk cartridge as described above, when the cartridge is inserted into the drive device and chucking has not been completed yet, the drive pin 2
2 is not engaged with the drive pin hole 3d of the center core member 3, the hub 3b is inclined. Even in this inclined state, the fixing flange 3a of the center core member 3 is fixed to the regulating rib 13a. To prevent the hub portion 3b of the center core member 3 from riding on the tapered portion 15 from the inner peripheral portion of the hub hole 2c (by forming the tapered portion 15). This makes it difficult to rotate.

The spindle shaft 20 rotates, the drive pin 22 is engaged with the drive pin hole 3d of the center core member 3, and the center core member 3 is sucked and held at the tip of the spindle shaft 20, and the center position and the height are in a predetermined state. The magnetic disk medium 4 is driven to rotate.

FIG. 4 shows another embodiment of the center core member 3. In the center core member 3, the entire fixing flange 3a and hub portion 3b are molded of resin, and a metal disk member 31 is integrally fixed to the bottom surface of the hub portion 3b. The disk member 31 is integrated with the resin portion by insert molding, bonding, or the like, so that the locking position accuracy with respect to the spindle shaft 20 is enhanced, and the magnet 23 attracts.

If the entire center core member 3 is formed by drawing of, for example, a stainless steel plate, deformation due to processing return occurs, the shape is distorted, and the dimensional accuracy is reduced. In some cases, the product does not satisfy the dimensional accuracy of the above, but as shown in FIG. 4, a metal that does not return and deform on the bottom surface of the hub portion 3b in contact with the tip of the spindle shaft 20 where the dimensional accuracy is most required. By using a resin molded product having the disc-made disk member 31, high dimensional accuracy can be obtained.

The disk member 31 is connected to the magnet 23.
May be provided only in the portion facing the center hole, or the inner diameter portion of the center hole 3c may be fixed.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an upper and lower shell of a magnetic disk cartridge and a magnetic disk medium according to an embodiment of the present invention.

FIG. 2 is a sectional front view of a main part of the magnetic disk cartridge of FIG. 1;

FIG. 3 is a cross-sectional front view of the main part showing a state where the center core member is inclined.

FIG. 4 is a cross-sectional view showing another embodiment of the center core member.

[Explanation of symbols]

 Reference Signs List 1 upper shell 2 lower shell 2c hub hole C case 3 center core member 3a fixing flange 3b hub 3c center hole 3d drive pin hole 4 magnetic disk media 5,6 liner 12 annular projection 13 regulating rib 15 taper section 20 spindle shaft 31 Metal disk member

Claims (2)

[Claims] 1. A disk-shaped flexible magnetic disk medium fixed to a fixing flange of a center core member is rotatably accommodated in a case formed by joining an upper shell and a lower shell, and a bottom surface of the lower shell is provided. In a magnetic disk cartridge having a hub hole in which a disc-shaped hub portion of the center core member is exposed at a substantially central portion, a tapered portion is provided by removing an inner corner portion of the hub hole in a chamfered shape. On the inner surface of the shell, a regulating rib protruding from the outer peripheral portion of the fixing flange of the center core member is protruded, and the restricting rib comes into contact with the fixing flange when the center core member is inclined, and the movement thereof moves. A magnetic disk cartridge, wherein the magnetic disk cartridge is disposed at a position where the magnetic disk cartridge is prevented from moving. 2. The magnetic disk cartridge according to claim 1, wherein the center core member is a resin molded product as a whole, and a metal disk member is fixed to a bottom surface of the hub portion.