JPS62197953A - Fixing device for information recording/reproducing disk - Google Patents

Abstract

PURPOSE:To positively reduce a moment to negate the return function of a disk to a level state, by forming especially a weak magnet attracting part on a magnet part at the opposite side facing with the disk driving pin of a chucking magnet. CONSTITUTION:In a chucking magnet 5 of C shape provided in a recessed shape within the upper plane annular recessed groove 2a of a flange 2, a weak magnet attracting part 5b for a center part magnet attracting plate 4 is formed on the magnet part at the opposite side facing with the driving pin 12 of the disk. By making thin a thickness B of the magnet in the weak magnet attracting part 5b less by a prescribed dimension than a thickness A in other part, and weakening an attracting force 10 against the center part magnet attracting plate 4 at the part, a moment 11 functioning to a disk 3 can be reduced. In this way, an inclination generated at the disk on the center protruding part of the flange is returned effectively to the level state with the moment of the disk itself.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fixing device for a magnetic disk or the like in an information device 1, such as a magnetic recording/reproducing device.

[Conventional technology]

Figures 4 and 5 show a conventional fixing device for this type of magnetic disk. In Figure 1, (1) is a rotating shaft driven by a motor, and (2) is the center integrally attached to this rotating shaft. (3) is a disk for recording and reproducing information; (4) is a central magnetic adsorption plate integrally provided with this disk; (5) is the above flange; A C-shaped chuck magnet (6) recessed in the annular groove (2a) bored in the upper surface protrudes from the space surrounded by this magnet, and is attached to the center of the disk (3). The top surface on which the magnetic adsorption plate (41 is placed)
6a) is a central protrusion that is integrally planted on the flange +21 so as to be located above the top surface (2b) of the outer peripheral rising wall of the flange (2) created by the annular groove (2a); It is.

Fig. 5 shows a case where an undesired tilt occurs when the disk +3) is placed, and (7) shows the central protrusion which becomes the tilting fulcrum of the disk (3) at that time. (6
), the outer circumferential edge of the top surface (6a) on the disk sinking side, (8) 12 Attraction force by the chuck magnet against the central magnetic adsorption plate (4) on the floating side in this inclined state, ( 91 is the disk (3) due to this suction force.
αG is the attraction force generated by the chuck magnet against the center magnetic adsorption plate (4) on the opposite sunken side, tIυ is the moment generated on the disk (3) by this attraction force, and aX5 is the moment generated on the disk (3) by this attraction force; This is the drive pin of the disk (3) that is set up on the flange (2) so as to be located within the cutout (5a) of the magnet (5).

[Problem that the invention seeks to solve]

In the above-mentioned conventional disk fixing means, when the disk (3) is placed, the disk moves toward the opposite side of the drive pin U3 to the outer peripheral edge (7) of the top surface (6a) of the central protrusion (6). ) as a tilting fulcrum as shown in Fig. 5, and the disc (3) returns to the horizontal state due to the -10,000 moment (9).
The other moment αυ (there was a problem in that it acted like a knife to cancel out the action of returning the disk to the horizontal state. This invention actively reduces the moment that cancels out the action of returning the disk to the horizontal state. With the goal.

[Means for solving problems]

In the case of this invention, a weak magnetic attraction part for the central magnetic attraction plate is specially formed on the magnet part on the opposite side facing the disk drive pin of the chuck magnet recessed in the annular groove on the upper surface of the flange. ing.

[For production]

In the case of this invention, the magnet section on the opposite side facing the disk drive pin is specially provided with a weak magnetic absorption section for the central magnetic attraction plate.

The suction force generated in this part is smaller than the suction force in other parts, and therefore the moment acting on the disc 5 is also small, which can cancel out the so-called return action of the disc to the horizontal state and weaken this moment.

〔Example〕

An embodiment of this invention will be described below. That is, first of all, in FIGS. 1 and 2, the same or corresponding parts as those in FIGS. (2) The upper annular groove (5) has a weak magnetic absorption part for the center magnetic adsorption plate (5b) on the opposite side of the magnet part facing the drive pin α of the disk. It is characterized by making +&@2 jb.T, that is, the thickness of the magnet in the part shown in Fig. 1 is made thinner by a predetermined dimension.
The attraction force α to the central magnetic adsorption plate (4) at the extracted portion is weakened to reduce the moment συ acting on the disk (3).

Further, FIG. 3 shows another embodiment of this invention.
In the case of figure (a), as a means of forming the above-mentioned weak magnetic absorption part (5b), the magnetizing force is weakened so that the surface magnetic flux density of the magnet in the extracted part is smaller than in other parts as shown in the figure. The moment αυ acting on the disk (3) is reduced, and as another means, as shown in Figure (B), the magnetization pitch in the weak & i air suction portion (5b) is changed from other parts. Compared to the magnetization pitch of , the absorption force against the central magnetic adsorption plate (4) is increased so that the pitch is 6 < 28. It is.

〔Effect of the invention〕

Since the fixing device of this invention is configured as described above,
The inclination of the disc on the central protrusion of the flange is very effectively returned to the horizontal state by the moment of the disc itself, and also eliminates variations in the attraction force of the entire magnet caused by missing parts of the chuck magnet. This has the effect that the horizontal holding performance of the disk can be improved with extremely simple means.

[Brief explanation of drawings]

Fig. 1 is a plan view showing a disc drive flange and a chuck magnet recessed in its annular groove in a fixing device of the present invention, and Fig. 2 shows a disc placed on these is inclined. FIG. 3 is a plan view corresponding to FIG. 1 showing another embodiment of the chuck magnet implemented in the present invention, and (A) and (B) are explanatory views thereof. . Furthermore, FIGS. 4 and 5 are views corresponding to FIGS. 1 and 2, showing conventional fixing devices. In the figure, (1) is the rotating shaft, (2) is the flange, (2a)
is an annular groove. (2b) Top surface of the outer peripheral rising wall of the Ic flange, (3)
is the disk, (4th machining center magnetic adsorption plate, (5) is the chuck magnet, (5a) is the missing part, (sb
) is the weak magnetic absorption part, (6) is the central protrusion of the flange,
(6a) shows the top surface, and α2 shows the drive pin of the disk. In other figures, the same reference numerals indicate the same or corresponding parts.

Claims (4)

[Claims] (1) A flange made of a non-magnetic material that is provided integrally with a rotating shaft driven by a motor and supports an information recording/reproducing disk, and is recessed in an annular groove bored in the upper surface of this flange. A C-shaped chuck magnet, which protrudes from the central space of the magnet and is arranged such that its top surface, on which the central magnetic adsorption plate of the disk is placed, is located above the top surface of the outer peripheral rising wall of the flange. A central protrusion integrally provided on the flange and a drive pin for a disk integrally planted on the flange so as to be located in the cutout part of the chuck magnet, wherein A fixing device for an information recording/reproducing disk, characterized in that a weak magnetic attraction portion for the central magnetic attraction plate is formed on the opposite side facing the drive pin. (2) The information recording/reproducing disk fixing device according to claim 1, wherein the thickness of the magnet of the weak magnetic attraction part formed on the chuck magnet is thinner than the thickness of the magnet of other parts. (3) The information recording/reproducing disk fixing device according to claim 1, wherein the magnetizing force of the magnet in the weak magnetic attraction part formed on the chuck magnet is weaker than the magnetizing force of the magnet in other parts. (4) The information recording/reproducing disk fixing device according to claim 1, wherein the magnetization pitch of the weak magnetic adsorption portion formed on the chuck magnet is sandwiched from the magnetization pitch of other portions.