JPH02230578A - Center core of flexible magnetic disk - Google Patents

Abstract

PURPOSE:To perform the positioning(centering) of a disk with high accuracy by forming a pair of tapered planes and the receiving plane of a flat spring for the pressing of a spindle on the tapered planes at the inner circumference of the center hole of a core member, respectively. CONSTITUTION:A pair of tapered planes 20a and 20b with which the circumferential plane of the spindle is abutted, and spring receiving planes 21a and 21b to support both end parts of the flat spring 35 to load the flat spring 35 which presses the spindle 40 on the pair of tapered planes 20a and 20b confronting with the tapered planes 20a and 20b in the center hole 19 of a center core are formed at the inner edge of the center hole 19 of the core member 18 made of sheet metal, respectively. Thereby, the positioning(centering) of the disk can be performed by pressing the spindle 40 on both tapered planes 20a and 20b by the flat spring 35, and also, since the position relation of the tapered planes 20a and 20b with the flat spring 35 is regulated by the spring receiving planes 21a and 21b, a constant spring pressing force without generating dispersion and being affected by the lapse of time can be obtained, and stable centering with high accuracy can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a center core of a flexible magnetic disk.

[Conventional technology]

FIGS. IA and IB are plan views of the front and back surfaces of a conventional disk cassette containing a flexible magnetic disk. This magnetic disk cassette 1 has a magnetic disk 3 rotatably housed in a flat case 2, and is used as a recording medium for an electronic camera incorporating a microcomputer, COD, etc. The magnetic disk 3 includes a center core 4 for mounting on a disk drive device,
This center core 4 is magnetically coupled to a drive shaft of a disk drive device through center holes 7 and 8 formed on the front and back sides of the case 2. For this purpose, a ring-shaped permalloy 9 that is 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 at the center of the center core 4. There is.

There are presser pad insertion openings 11 on the front and back sides of the case 2.
and a head insertion opening 12 are formed therein, and a sliding shutter 10 is provided in the case 2 to close these openings 11 and 12 when the unit 1 is not in use.

The center core 4 is molded from resin, and its svintl hole 5 is defined by a V-shaped tapered surface 14 and a thin plate-shaped spring surface 15.

The spin 1 spring surface 15 inserted into the hole 5 presses against the tapered surface 14, thereby centering the disk.

(Problems to be Solved by the Invention) Since the entire center core 4 used in the above-mentioned conventional technique f+jy is formed by resin molding, the dimension between the tapered surface 14 and the spring 15 when molded is This tends to vary and changes over time, resulting in misalignment of the disk and eccentricity in disk rotation.Also, since the spring surface 15 is made of resin, due to dimensional variations during molding and changes over time, It was difficult to apply and maintain spring force.

The present invention is aimed at solving the problems mentioned in -1 and 2 above, and providing a center core structure with extremely high disk centering accuracy.

Means for Solving Problem 1] The center core of the flexible disk according to the present invention holds the flexible magnetic disk 38 and inserts the spindle 40 of the disk drive device in order to center the disk. It is provided with a center hole, and has a center hole 19.
The center hole 19 of the core member 18 has a pair of tapered surfaces 20a and 20b in contact with the peripheral surface of the spindle, and A spring receiving surface 2 that supports both ends of the plate spring 35 in order to mount the plate spring 35 that presses the plate spring 35 against the pair of tapered surfaces in the center hole of the center core so as to face the tapered surfaces. ．． a, 211] are formed respectively, and this configuration enables highly accurate centering.

〔Example〕

The configuration of the tree invention will be described below with reference to embodiments.

FIG. 2 is a plan view of a sheet metal core member 18 forming the main part of the center core of the flexible magnetic disk according to the present invention;
The figure is a sectional view taken along the line A--A in FIG. 2. This core shrine 18
is made by punching a soft iron plate or the like into a ring shape, and has a pair of tapered surfaces 20a, 20 around the center hole 19.
b and a pair of spring bearing iJ surfaces 21a and 2lb are formed. The spring receiving surfaces 21a and 21b are perpendicular to the line A-A.

This core member 18 also acts as a yoke material that is attracted to the chassis king magnet 1 of the disk drive device. Therefore, the permanent eye ring 9 as shown in FIG. IB is not necessary.

The shape of the core member 18 is symmetrical about the line AA as shown in FIG. 2, and a bent portion 22 is formed on the line AA around the inner circumference of the center hole 19.

This bent portion 22 faces the rotation detector of the disk drive device, and the rotation detector detects the leakage magnetic flux of the chucking magnet, thereby obtaining a pulse indicating the rotational phase of the disk. It looks like this. This bent part is provided at the line A-A]2, so the core part tA'
1 It is easy in terms of design to take the rotational dynamic harance of B itself, for example, as shown in Fig. 2, the core part 1
By providing the cutout portion 23 on the A-8 line around the outer periphery of the core portion 18, it is possible to obtain the core portion 18 with a good dynamic balance.

Around the center hole 19 of the core member 18, as shown in the plan view of FIG. 4 and the cross section taken along the line B-B in FIG. - Attached by molding. The diameter of the outer circumferential surface 26 of this ring member matches the inner diameter of the center hole of the magnetic disk, and the disk is positioned and fixed to the core member 18 by this outer circumferential surface 26. In addition, the outser 1 of the ring member 25
-A ring-shaped rib 27 for disk welding is formed on the lower surface of the outer periphery of the core member 18 at the same time as the molding. A plurality of holes 28 and grooves 29 are formed around the outer periphery of the core member 18 in order to outsert mold the ribs 27 onto the core part IFA18.

The center hole 30 of the ring member 25 is smaller as a whole 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 sectional view taken along the line CC in FIG. 4, it protrudes from the inner circumferential surface 31 of the center hole 30 of the ring member 25. This allows the peripheral surface of the spindle to come into contact with the tapered surfaces 20a, 20b. The inner circumferential surface 32 of the center hole 30 of the ring portion 25 below the core member 18 has a tapered surface 20a or 2 as shown in FIG.
This prevents the spindle from coming into direct contact with the edge of the tapered surface 20a, making it easier to insert the spindle and preventing the spindle from being scraped and centering accuracy decreasing.

Slits I-34a, 34 are formed in the ring-shaped member 25 at portions corresponding to the spring receiving surfaces 21a, 2lb of the core member 18.
b is formed, and the leaf spring 35 shown in the seventh section is inserted here. The spring receiving surfaces 21a, 2lb of the core member 18 are located approximately in the center of the width of the slits 34a, 34b, and when the leaf spring 35 is inserted, the spring receiving surfaces 21a, 2l
The leaf spring 35 is supported in the radial direction by b.

Further, protrusions 36a and 36b are formed on both sides of the leaf spring 35, and the protrusions engage the core member 18 within the slits 34a and 34b, thereby supporting the leaf spring 35 in the axial direction.

The leaf springs 35 are attached to the slits 34a and 34b as described above, and the magnetic disk 3B 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. By fitting the cap member 39 shown in the perspective view of FIG. 8 and the cross-sectional view of FIG. Complete.

In this state, as shown in FIG. 11 (cross section along the leaf spring 35), the slits 34a and 34b into which the convex parts 36a and 36b at both ends of the leaf spring 35 are inserted are covered by the cap member 39, so that the leaf spring 35 will never fall off.

FIG. 12 is a partially detailed view showing the state in which the spindle 40 of the disk drive device is inserted into the hole in the center core of the disk. As shown in FIG.
By being pressed by the disc, positioning (centering) of the disc is performed. Therefore, highly accurate centering is performed without variation in accordance with the dimensional accuracy of the punched sheet metal core member 18. Further, since the positional relationship between the tapered surfaces 20a, 20b and the leaf spring 35 is defined by the spring receiving surfaces 21a, 2lb formed on the core member 18, a constant spring holding force without variation or change over time can be obtained. Stable and highly accurate centering can be performed.

〔Effect of the invention〕

As described above, in the present invention, a pair of tapered surfaces and a receiving surface for a leaf spring for pressing the spindle against the tapered surfaces are formed around the inner periphery of the center hole of the core member made of sheet metal. The positioning (centering) of the sheet metal core member can be performed without variation or change over time, depending on the dimensional accuracy of the core member of the sheet metal. In addition, since the positional relationship between the tapered surface and the leaf spring is determined by the spring receiving surface formed on the core member together with the tapered surface, it is possible to obtain a spring pressing force of the spindle that does not vary or change over time. Disc centering can be performed.

[Brief explanation of the drawing]

FIGS. IA and IB are front and back views, respectively, of a conventional magnetic disk cassette, FIG. 2 is a plan view of a sheet metal core member forming the main part of the flexible magnetic disk according to the present invention, and FIG. 2, q l0 Figure 4 is a plan view of the core member in Figure 2 in which a ring material as a disk core material is outsert molded, and Figure 5 is a cross-sectional view taken along line B-- in Figure 4. 6 is a partial sectional view taken along line C-C in FIG. 4, FIG. 7 is a plan view of the leaf spring, and FIG.
FIG. 9 is a vertical sectional view of FIG. 8, FIG. 10 is a sectional view of the assembled disk center core, and FIG. FIG. 12 is a cross-sectional view of the center core along the leaf spring, and a partially detailed view of the spindle inserted into the center core. In addition, in the reference numerals used in the drawings, ] 8--------------- Core member 1
9--1---1-------- Center hole 2 0
a, 20 b---- Tapered surface 21a,
2 l b------ Spring receiving surface 2 5 ---
------ - Ring section 34a, 34b--
−−− Slit 3 5−−−−−−−−−−−−−−
Jutan spring 3 8------------------
-It is a magnetic disk. ＼ Camping parts spindle

Claims (1)

[Claims] A center core of a flexible disk having a center hole into which a spindle of a disk drive device is inserted for holding a flexible magnetic disk and centering the disk, comprising a sheet metal core member having the center hole. The center hole of the core member has a pair of tapered surfaces in contact with the circumferential surface of the spindle, and a leaf spring that presses the spindle against the pair of tapered surfaces is disposed inside the center hole of the center core. 1. A center core for a flexible magnetic disk, characterized in that spring receiving surfaces are formed to support both ends of the leaf spring so as to be mounted facing the tapered surface.