JPH0722772Y2 - Magnetic disk cartridge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a magnetic disc cartridge which rotatably accommodates a magnetic disc sheet, which is a disc-shaped ultra-thin recording medium, and more specifically, a center of the magnetic disc sheet. An improved magnetic disc cartridge for a core.

[Prior art]

A magnetic disk cartridge such as a so-called video floppy for still image recording using a flexible magnetic disk sheet with a diameter of 47 mm has a center core at the center of the sheet, and an electronic still camera or an electronic still camera is provided at the center of the center core. A center hole into which a spindle of a recording / reproducing device such as a television photo player is fitted is formed. When the magnetic disk cartridge is loaded in the recording / reproducing apparatus, the rotary drive spindle is inserted into the center hole of the center core to position the magnetic disk, and the center core is magnetically attached to the magnetic chuck. Driven to rotate.

The center core includes a spring portion that urges the spindle when the spindle is fitted, and the spring portion urges the spindle in one direction to position the center core concentrically with the spindle.

As shown in FIGS. 3 and 4, the conventional center core comprises a core plate made of metal, a center hole 15, and an annular rib 13 made of synthetic resin having a spring portion 14. The core plate 12 is provided with a plurality of plate holes 16 and groove portions 18 are formed so as to connect the plate holes 16 two by two.
The core plate 12 and the annular rib 13 are connected by the structure of the plate hole 16 and the groove portion 18. That is, when the core plate 12 and the annular rib 13 are integrally molded by outsert molding, for example, the resin flowing from the annular rib 13 of synthetic resin into the plate hole 16 fills the groove portion 18 and connects the plate holes 16 to each other. Are bound by attaching to.

However, since the groove portion 18 of the core plate 12 is generally formed by drawing, there is a problem that the flatness of the core plate 12 is lowered during the processing, which adversely affects the performance of the magnetic disk cartridge. That is, since the magnetic disk sheet (medea) is magnetically attached to the magnetic chuck portion and the core plate of the recording / reproducing apparatus and is rotationally driven, the rotatability of the magnetic disk sheet is reduced as the flatness of the core plate 12 decreases. However, there is a problem in that the head contact between the sheet and the magnetic head becomes worse.

[Purpose of device]

The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetic disk cartridge having a center core capable of ensuring good rotation of the magnetic disk sheet.

[Constitution of device]

The above object of the present invention is to provide a center formed by connecting an annular rib made of synthetic resin and a metal core plate to which the magnetic disk sheet is attached, in the center of the magnetic disk sheet into which a spindle for rotation drive is inserted. In a magnetic disk cartridge provided with a core, a plurality of plate holes formed in the core plate are formed so that the inner diameters thereof are small toward the protruding side of the annular rib, and the molten resin when the annular rib is injection-molded Flow into the plate hole so that a part of the annular rib is fitted into the plate hole, so that the core plate and the annular rib are coupled to each other. Achieved by a cartridge.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a plan view of a main part of an embodiment of a magnetic disk cartridge according to the present invention, and FIG. 2 is an enlarged sectional view of the main part taken along the line AA of FIG.

The center core 1 shown in FIG. 1 is a magnetic disc sheet 9 rotatably housed in a magnetic disc cartridge.
It is provided in the center of (see FIG. 2) as in the conventional case, and is composed of an annular rib 3 having a center hole 5 and a spring portion 4 and a core plate 2.

The annular rib 3 is made of a synthetic resin having appropriate wear resistance such as ABS resin or polycarbonate, while the core plate 2 is made of a metal material which can be magnetically attached by the magnetic tick portion of the recording / reproducing apparatus. The annular rib 3 and the core plate 2 are connected to each other such that a part of the annular rib 3 fits into a plurality of plate holes 6 provided in the core plate 2. That is, as shown in FIG. 2, the plate hole 6 is formed in a tapered shape such that the inner diameter thereof is narrowed toward the protruding side of the annular rib 3 (downward in the drawing), so that the plate hole 6 enters the plate hole 6. The fitting portion 7 made of synthetic resin can be coupled so as not to come off. The annular rib 3 and the core plate 2 can be integrally molded by, for example, outsert molding or the like as in the conventional case.

The plate hole 6 of the core plate 2 is extremely easily provided by punching or the like. Therefore, there is almost no plate deformation around the plate hole 6, and the plate flatness is very good as compared with the conventional core plate 12 in which the narrowed portion 18 is formed. As a result, rattling at the time of magnetic attachment between the core plate 2 and the magnetic chuck portion is prevented, and the flatness of the magnetic disk sheet 9 attached to the core plate 2 is maintained well, so that the sheet rotation is prevented. The property becomes extremely good.

[Effect of device]

As described above, the magnetic disc cartridge according to the present invention has a structure in which the core plate of the center core provided at the center of the magnetic disc sheet and the annular rib are not provided with a throttle portion in the core plate. Since the flatness of the core plate can be made extremely good, it is possible to avoid the distortion of the magnetic disk sheet attached to the core plate and to make the magnetic adhesion between the core plate and the magnetic stick part desired. it can. As a result, the magnetic disk cartridge according to the present invention suppresses the deviation in the sheet thickness direction during rotation of the magnetic disk sheet, so that the head touch with the magnetic head is kept extremely good, and excellent recording / reproducing without dropout etc. Can be guaranteed.

[Brief description of drawings]

FIG. 1 is a plan view of a center core according to an embodiment of the present invention,
2 is an enlarged view of a cross section taken along line AA of FIG. 1, FIG.
FIG. 4 and FIG. 4 are plan views of a conventional center core and its B.
FIG. 6 is a cross-sectional view taken along the line B. 1,10 …… Center core, 2,12 …… Core plate, 3,13…
… Annular rib, 4,14 …… Spring part, 5,15 …… Center hole, 6,
16: Plate hole, 7: Fitting part, 9: Magnetic disk sheet, 18: Drawing part, 20: Spindle.

Claims (1)

[Scope of utility model registration request] 1. A center core formed by coupling an annular rib made of synthetic resin and a metal core plate to which the magnetic disk sheet is attached, in the center of a magnetic disk sheet into which a spindle for rotational drive is inserted. In the provided magnetic disk cartridge, the inner diameter of the plurality of plate holes provided in the core plate is formed to be small toward the protruding side of the annular rib, and the molten resin when the annular rib is injection-molded is A magnetic disk cartridge characterized in that the core plate and the annular rib are connected to each other by having a structure in which a part of the annular rib is fitted into the plate hole and is fitted into the plate hole.