JP2001357647A - Magnetic disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability by reducing a plane tilt of a magnetic recording medium in adhesion between a central core member and the medium. SOLUTION: When a flange 3b for fixing the central core member 3 is fixed to the inner peripheral part of the disk-like flexible magnetic recording medium 2 by the use of an adhesive 5, coating of the adhesion 5 to the fixing flange 3b is started from the position B where the plane tilt of the medium becomes minimum when the magnetic recording medium 2 is fixed to the central core member 3. The plane tilt is reduced by preventing the coating starting position where the coating thickness of the adhesive becomes large from being overlopped with the deforming position by working of the fixing flange 3b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk having a center core member fixed to an inner peripheral portion of a disk-shaped, particularly large-capacity flexible magnetic recording medium built in a magnetic disk cartridge or the like. is there.

[0002]

2. Description of the Related Art Conventionally, a flexible magnetic recording medium in which magnetic layers are formed on both sides of a disk-shaped support made of a flexible polyester sheet or the like is driven to rotate, and a magnetic head applies magnetic force to the magnetic layer. A magnetic disk cartridge in which a magnetic disk (flexible disk) for recording is accommodated in a flat case is provided, and is mainly used as a recording medium for a computer due to advantages such as easy handling and low cost.

In addition, a chuck provided at an end of a spindle shaft of drive-side rotation driving means is provided on an inner peripheral portion of the flexible magnetic recording medium, supporting the magnetic recording medium and defining a rotation center thereof. The center core member is fixed so as to be engaged with and held by the portion and transmit the rotational driving force.

With the increase in the recording capacity of the magnetic recording medium as described above, it is necessary to rotate the magnetic disk at a high speed in order to secure the transfer rate. The height of the magnetic head for recording / reproducing is such that the desired recording / reproducing performance can be ensured by strictly maintaining a proper proper positional relationship.

[0005]

However, in the case of a flexible magnetic recording medium, it is difficult to maintain a strict positional relationship with the magnetic head due to the occurrence of surface deflection during rotation.

A cause of the above-mentioned surface run-out is that the height of the peripheral surface of the fixing flange of the center core member to which the magnetic recording medium is attached is not uniform from the reference surface (flat surface) chucked on the drive side. In addition to this, due to the non-uniform application of the adhesive to the fixing flange, if the effects of both overlap, the maximum value of the runout of the magnetic recording medium after fixing may be larger than the allowable value. is there.

[0007] The non-uniformity of the fixing flange is caused by the processing accuracy at the time of manufacturing the center core member from the metal plate by press molding. In particular, the fixing flange has a spindle hole at the center position of the reference surface and is driven to the eccentric position. In a structure having holes, the height of the media attachment surface of the fixing flange near the drive holes tends to decrease with the punching of the drive holes. Also, the amount of the adhesive applied at the application start position (end position) tends to be large, and when the application start portion having a large application amount comes to the portion where the height is low, the adhesive thickness at this portion is reduced. The media height position becomes the lowest, and the media surface deflection becomes large, which may affect the magnetic recording / reproducing characteristics.

In other words, the formation of the drive hole in the production of the center core member is performed by holding the reference surface in a die-shaped lower die and pressing and punching with a punch-shaped upper die. The force acts downward on the reference surface side, and the height of the fixing flange in a portion near the drive hole at the eccentric position is deformed toward the reference surface side from other portions and becomes lower. In addition, the flatness of the flange surface may be uneven due to other factors.

In view of the above circumstances, the present invention has been made to provide a magnetic disk in which the media surface deflection during the bonding between a center core member and a magnetic recording medium is reduced to enhance reliability.

[0010]

According to the magnetic disk of the present invention which has solved the above-mentioned problems, a fixing flange of a center core member is fixed to an inner peripheral portion of a disk-shaped flexible magnetic recording medium using an adhesive. When the magnetic recording medium is fixed to a center core member,
The application of the adhesive to the fixing flange is started from a position where the media surface runout is minimized.

For example, an adhesive is provided on an inner peripheral portion of a disk-shaped flexible magnetic recording medium by attaching a fixing flange of a center core member having a spindle hole at a center position of a disk portion and a drive hole at an eccentric position. In the magnetic disk fixed by using the magnetic disk, the application of the adhesive to the fixing flange is started from a position close to a portion rotated by 180 ° about the spindle hole from the drive hole of the center core member. is there.

[0012]

According to the magnetic disk of the present invention as described above, the fixing flange of the center core member is fixed to the inner peripheral portion of the magnetic recording medium using an adhesive. When the adhesive is applied to the fixing flange from the position where the media surface runout is minimized, the height of the fixing flange is slightly uneven due to the processing accuracy of the center core member. Even if there is, the position where the surface runout is minimized is increased by the amount of adhesive applied, and even if the surface runout of this part increases, the original surface runout is small, so the maximum surface runout as a whole , And good magnetic recording / reproducing characteristics can be secured to improve reliability.

For example, when a fixing flange of a center core member having a driving hole in a disk portion is fixed to the inner peripheral portion of the magnetic recording medium by using an adhesive, the center hole is moved from the driving hole of the center core member to the center of the spindle hole. When the application of the adhesive to the fixing flange is started from a position close to the portion rotated by 180 °, that is, a position where the surface runout is reduced, the amount of the adhesive applied to the deformed portion due to the punching of the driving hole becomes large. By preventing the start position from coming, the increase in the amount of surface runout due to the overlap of the two is suppressed, and the position where the surface runout is reduced is increased so as to increase the application amount, thereby reducing the overall maximum surface runout. The magnetic recording / reproducing characteristics can be secured and reliability can be improved.

[0014]

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 magnetic disk of the present embodiment, FIG. 2 is a sectional view of a main part, and FIG. 3 is a bottom view of a center core member. In the drawings, the thickness and the like are shown at different ratios from actual dimensions.

The magnetic disk 1 is composed of a disk-shaped flexible magnetic recording medium 2 and a center core member 3 for rotational driving fixed to the center of the magnetic recording medium 2.

The magnetic recording medium 2 has a magnetic layer formed on both sides of a flexible support made of polyethylene terephthalate (PET) or the like, and is provided in a disk shape having a center hole 2a opened.

The center core member 3 is formed by stamping a plate-shaped metal material made of a ferromagnetic material such as a magnetic stainless steel into a predetermined shape and press-forming the plate-shaped metal material. Fixing flange 3 extending to
b, and a connecting portion 3c that rises in a cylindrical wall shape connecting the outer peripheral edge of the disk portion 3a and the inner peripheral edge of the fixing flange 3b. Then, the fixing flange 3b is fixed to the inner peripheral portion of the magnetic recording medium 2 using an adhesive 5 (see FIG. 2).

The disk portion 3a is provided with a spindle hole 3d opening at the center of rotation and a driving hole 3e opening at an eccentric position on the outer peripheral side of the spindle hole 3d. The rotation is carried out while being held by the magnetic chuck part.

The disk portion 3a has a step formed in the middle,
The bottom surface of the circular portion on the side of the spindle hole 3d serves as a reference surface that comes into contact with the tip surface of the spindle shaft, and the annular portion on the outer periphery serves as a suction surface facing the magnet of the spindle shaft. In addition, the lower surface of the fixing flange 3b is a media attaching surface parallel to the reference surface of the disk portion 3a, and the adhesive 5 is applied to the attaching surface in an annular shape, and the magnetic recording medium 2 is attached. The circumferential deviation of the height between the reference surface and the sticking surface in the circumferential direction is a first cause of the medium surface runout, and the difference in the applied thickness of the adhesive 5 is the second cause of the medium surface runout.

When the magnetic recording medium 2 is fixed to the center core member 3, the adhesive 5 is applied to the fixing flange 3 b on the circumference starting from a position where the medium surface deflection is minimized. The application thickness at the application start position (end position) is thicker than other portions.

Specifically, as shown in FIG. 3, the spindle hole 3 is moved from the rotation phase position A of the opening position of the drive hole 3e.
The application of the adhesive 5 is started from the fixing flange 3b in a portion close to the phase position B rotated by 180 ° about d. The fixing flange 3b in the vicinity A of the drive hole 3e is deformed so as to be lowest with respect to the reference surface along with the punching of the drive hole 3e on the reference surface side. The fixing flange 3b of the application start portion B has the highest surface runout without being affected by the influence, and the adhesive application is started from this portion.

When assembling the magnetic recording medium 2 with the center core member 3, the magnetic recording medium 2 is placed flat on a jig with its center position regulated, and the lower surface of the fixing flange 3b is placed from above. A center core member 3 in which a predetermined amount of an adhesive 5 is applied to a predetermined position from the start position on the circumference.
Is held down by a transport jig, and moved downward while positioning the center positions of both, so that the bonding surface of the fixing flange 3b is pressed against the inner peripheral portion of the magnetic recording medium 2 and the adhesive 5 is pressed.
By joining.

According to this embodiment, the fixing flange 3b
The application of the adhesive 5 to the affixing surface is performed from a portion where the surface runout is small, such as a portion opposite to the drive hole 3e, and a portion where the surface runout becomes large due to deformation during processing, such as the vicinity of the drive hole 3e. Then, the magnetic recording medium 2 after fixing is fixed so as not to coincide with the application start portion where the application amount of the adhesive 5 becomes large.
The maximum value (PP value) between the upper peak and the lower peak of the surface runout amount generated by the rotation of (1) is reduced. Thereby, the positional relationship with the magnetic head at the time of recording / reproducing is properly maintained,
An error can be prevented and reliability can be improved.

The disk portion 3 of the center core member 3
The shape a may be provided in a flat shape without a step in the middle as described above.

The magnetic disk 1 is rotatably housed in a flat case formed by joining an upper shell and a lower shell made of, for example, a synthetic resin. The case has an opening for inserting a magnetic head. A circular hub hole is formed in the inner peripheral portion of the lower shell so as to have a size facing the engaging portion of the center core member 3.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a magnetic disk according to one embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a magnetic disk.

FIG. 3 is a bottom view of the center core member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic disk 2 Magnetic recording medium 3 Center core member 3a Disk part 3b Fixing flange 3d Spindle hole 3e Drive hole 5 Adhesive B Adhesive application start position

Claims (1)

[Claims] 1. A magnetic disk in which a fixing flange of a center core member is fixed to an inner peripheral portion of a disk-shaped flexible magnetic recording medium using an adhesive, wherein the magnetic recording medium is fixed to the center core member. Wherein the application of the adhesive to the fixing flange is started from a position where the media surface runout is minimized.