JPH0619891B2 - Magnetic disk pressing mechanism for magnetic recording / reproducing apparatus - Google Patents

Description

TECHNICAL FIELD The present invention relates to a magnetic recording / reproducing apparatus for recording / reproducing a flexible magnetic disk, and more particularly to a magnetic disk pressing mechanism for pressing a magnetic disk against a magnetic head.

"Prior Art and Problems Thereof" This type of magnetic recording / reproducing apparatus is used in an electronic still camera that converts a video signal into an electric signal and stores the electric signal. In this device, in order to surely bring the magnetic disk into contact with the magnetic head, a stabilizer is positioned on the opposite side of the magnetic head, and the stabilizer presses the magnetic disk against the magnetic head. This stabilizer is a type that directly presses the back surface of the magnetic head, and a portion corresponding to the magnetic head is provided as a recess, and the bending rigidity of the disk is utilized by pressing the magnetic disk on the back side edge of the magnetic head. It is known to be an indirect pressing type that brings it into contact with a magnetic disk, and in an electronic still camera,
The latter indirect pressing type is adopted.

4 to 9 are views for explaining the structure and problems of the conventional indirect pressing type. As shown in FIGS. 4 and 5, the magnetic disk 11 has a support hole 11 a at the center thereof in the center hub 13 of the spindle motor 12.
It is supported by and rotates. A magnetic head 14 and a stabilizer 15 are located on the front and back of the magnetic disk 11, and
A concave portion 16 is formed in the radial direction of the magnetic disk 11 corresponding to the moving direction of the magnetic head 14.
Further, the tip end of the stabilizer 15 in the radial direction of the magnetic disk is a pressing surface 17 that contacts the magnetic disk 11, and this pressing surface 17 suppresses the vibration of the magnetic disk 11 during running (rotation), and also to each track. The magnetic head 14 is made to contact stably.

The above magnetic recording / reproducing apparatus, as exaggeratedly shown in the figure,
The magnetic disk pressing surface 15a of the stabilizer 15 is brought into contact with the magnetic disk 11 to bend the magnetic disk 11 into the concave portion 16, and the rigidity thereof causes the magnetic disk 11 to move to the magnetic head 1.
Recording and reproduction are performed in a state of being in contact with 4. At this time, the upper surface of the magnetic disk 11 supported by the spindle motor 12 in the vicinity of the support hole 11a and the magnetic disk 11 of the stabilizer 15 are supported.
When a gap A is formed between the contact surface with the magnetic disk, that is, the magnetic disk pressing surface 15a, the dimension B from the lower end 13a of the center hub 13 to the upper surface of the magnetic disk 11 has a certain tolerance depending on different magnetic disks 11. The following problems occur. FIG. 6 shows the state of the dimensional variation due to the tolerance of the magnetic disk 11 by ± B '. Even if the protrusion amount of the magnetic head 14 with respect to the stabilizer 15 is determined to be C on the device side, If the dimension B is different, when the magnetic disk 11 is considered as a double-supported beam, the height of one fulcrum is not constant as shown by ± B '. Then, the contact pressure between the magnetic head 14 and the magnetic disk 11 is not constant, and the contact becomes unstable.

Therefore, as shown in FIGS. 7 and 8, the spindle motor 12 is slightly lifted with respect to the magnetic head 14 and the stabilizer 15, and the dimension B from the lower surface 13a of the center hub 13 to the upper surface of the magnetic disk 11 is -B '. An apparatus has been proposed which can secure the dimension D from the magnetic disk pressing surface 15a of the stabilizer 15 to the upper surface of the magnetic disk 11 even with a tolerance of. According to this device, when the magnetic disk 11 is considered as a double-supported beam, even if the center hub 13 (support hole 11a of the magnetic disk 11) moves up and down as shown in FIG. Supports 17s and 18s are formed on the pressing surface 17 and the innermost portion 18, respectively. Therefore, since the deflection amount E of the magnetic disk 11 by the two fulcrums 17s and 18s and the magnetic head 14 is constant regardless of the magnetic disk 11, the problem that the contact pressure becomes unstable is avoided. .

However, in this device, the following problems occur. FIG. 9 is a sectional view taken along the line IX-IX in FIG. 4, but when the magnetic disk 11 rotates, the magnetic disk 11 has a space between the pressing surface (outermost part) 17 and the innermost part 18 of the stabilizer 15.
It floats above the magnetic head 14. However, at the pressing surface 17 and the innermost portion 18, the flying height of the magnetic disk 11 with respect to the magnetic head 14 is reduced due to the lateral leakage of the air flow. That is, even if the flying height of h0 can be secured in the middle of the radial direction of the magnetic disk 11, only the flying heights of h1 and h2 can be secured on the pressing surface 17 and the innermost portion 18, respectively. Especially near the innermost portion 18 of the stabilizer 15, the magnetic disk 11 also tends to move away from the stabilizer 15 due to levitation near the center in the radial direction, but since the bending rigidity of the magnetic disk 11 itself cancels this, the magnetic disk 11 as a whole is The flying height cannot be secured. Especially, in this portion, the contact between the magnetic disk 11 and the stabilizer 15 has a shape close to a line contact or a point contact, which causes damage to the magnetic disk 11 and the stabilizer 15, which causes frequency jitter of the recording / reproducing signal. Cause it to happen.

"Object of the Invention" An object of the present invention is to solve the above problems of the conventional magnetic recording / reproducing apparatus and to obtain an apparatus in which the stabilizer does not damage the magnetic disk.

"Outline of the Invention" The present invention was made as a result of reviewing that the entire pressing surface of the conventional stabilizer in the radial direction of the magnetic disk is a plane parallel to the magnetic disk. And a sloped surface that is located inside the magnetic disk in the radial direction and that is in a direction away from the magnetic disk and that has a uniform cross-sectional shape in the circumferential direction. .

"Examples of the Invention" The present invention will be described below with reference to illustrated examples. Figure 1 shows
In the embodiments of the present invention, the same parts as those of the conventional device are designated by the same reference numerals. Unlike the conventional product, the magnetic disk pressing surface 15a of the stabilizer 15 according to the present invention is a plane 15b parallel to the magnetic disk 11 outside the substantially center of the magnetic disk 11 in the radial direction, and an inside thereof in a direction away from the magnetic disk. The inclined surface 15c is used. Plane 15b
Similar to the device shown in FIG. 7, its position is set so that the dimension D from the plane 15b to the upper surface of the magnetic disk 11 can be secured. On the other hand, the maximum amount of withdrawal from the flat surface 15b due to the inclination of the inclined surface 15c (the magnetic disk 11
The length d in the direction of escape from is smaller than the displacement amount in the vicinity of the innermost portion 18 due to the bending of the floating of the magnetic disk near the center of the stabilizer 15, and is a finite amount.

In the apparatus having the above-mentioned configuration, the magnetic disk 1 is attached to the center hub 13.
When the spindle motor 12 is supported and rotated by the spindle motor 12, the largest flying height h0 is obtained in the central portion in the radial direction by the air flow due to the rotation of the magnetic disk 11 as in the conventional apparatus, and the maximum amount of the stabilizer 15 is increased. Although the flying heights at the outer and innermost portions are smaller than this, according to the present invention, the magnetic disk 11 and the stabilizer 15 do not come into contact with each other. The reason will be described with reference to FIGS. 2 and 3.

FIG. 2 shows the magnetic disk 11 as a beam and models its deformation. The right end of the drawing is the center hub 1.
Stabilizer 1 showing the maximum flying height, considering it as a fixed end for 3
5 shows a state in which the vicinity of the center of 5 is pushed down by a force P. Here, the amount of flexure is D + h0, which is the amount of flexure D pushed down by the flat surface 15c of the stabilizer 15 plus the flying height h0.
Is the levitation force due to the air flow accompanying the rotation of the magnetic disk 11. Note that the force P is actually a mountain-shaped distributed load, not a concentrated load, but is treated as a concentrated load for convenience. Further, Q in the figure shows the magnetic head protrusion output when the magnetic head 14 is located outside the stabilizer 15, that is, when it is located on a track near the outer circumference. The amount of bending of the magnetic disk 11 due to the protrusion of the magnetic head is E shown in FIG. 8 when the magnetic disk 11 is stopped,
During rotation, the flying height h0 is added as shown by the broken line, resulting in E + h0. And the deformation amount of the magnetic disk 11 is
It gradually decreases from the point of action of P, and the center hub 13
Leading to.

On the other hand, when the magnetic head 14 is located closer to the center hub 13 than the center of the stabilizer, as shown in FIG.
As shown by the broken line, the magnetic disk 11 also has a bending amount of E + h0. This bending amount is the amount with respect to the point where P is added, and the magnetic disk 11 is inclined up to the portion supported by the center hub 13 as described above. Therefore, the actual protrusion amount of the magnetic head 14 with respect to the magnetic disk 11 must be subtracted from the difference δ in the amount of deflection at the point Q due to the force P. That is, the amount is E + h0-δ.
Therefore, the protrusion output Q of the magnetic head 14 with respect to the magnetic disk 11 in FIG. 3 is different from that in FIG.
However, the magnetic disk 11 has a disk shape, the bending rigidity becomes higher toward the center side, and the same protrusion output can be obtained even with a small amount of bending.

With respect to such deformation of the magnetic disk 11, the stabilizer 15
Has an inclined surface 15c on the inner side thereof, and the maximum withdrawal amount d from the flat surface 15b is set to be slightly smaller than the amount of deflection of the magnetic disk in the vicinity of the innermost circumference of the stabilizer 15, and Since it has a finite size, it is possible to ensure the floating of the magnetic disk 11 in the innermost part 18 of the stabilizer 15. That is, the magnetic disk 11 does not come into contact with the stabilizer 15 when the magnetic disk 11 rotates.

[Advantages of the Invention] As described above, in the magnetic recording / reproducing apparatus according to the present invention, the magnetic disk pressing surface is positioned inside the radial direction of the magnetic disk on the surface of the stabilizer facing the magnetic disk. Since the inclined surface that escapes from the magnetic disk and has the uniform cross-sectional shape in the circumferential direction is formed, the inside of the inclined surface does not come into contact with the stabilizer during rotation of the magnetic disk. Therefore, it is possible to prevent the stabilizer from scratching the inner and outer peripheral portions of the magnetic disk and prevent frequency jitter.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a magnetic disk pressing mechanism of a magnetic recording / reproducing apparatus according to the present invention, and FIGS. 2 and 3 are models showing deformation of a magnetic disk by the pressing mechanism according to the present invention as a model. 4 and 5 are sectional views taken along line IV-IV in FIG. 5, showing examples of a conventional magnetic disk pressing mechanism, FIG. 5 is a sectional view taken along line VV in FIG. 4, and FIG. Is a skeleton diagram for explaining the problems in the conventional apparatus shown in FIGS. 4 and 5, FIG. 7 is a vertical sectional view showing an example of another conventional magnetic disk pressing mechanism, and FIG. FIG. 9 is a skeleton diagram showing the state of deformation of the magnetic disk in the apparatus, and FIG. 9 explains the problems of the apparatus of FIG.
It is sectional drawing which follows the IX line. 11 ... Magnetic disk, 12 ... Spindle motor, 1
3 ... Center hub, 14 ... Magnetic head, 15 ... Stabilizer plate, 15a ... Magnetic disk pressing surface, 15b ... Flat surface, 15c ... Inclined surface, 16 ... Recessed surface, 17 ... Pressing surface (outermost side) Part), 18 ... the innermost part.

Claims (1)

[Claims] 1. A flexible magnetic disk is provided with a magnetic head for recording and reproducing data on and from the magnetic disk and a stabilizer having a recess at a portion corresponding to the magnetic head. In a magnetic disk pressing mechanism of a magnetic recording / reproducing device for pressing a disk into contact with a magnetic head, a direction of escaping from the magnetic disk by being positioned inside the magnetic disk in a surface of the stabilizer facing the magnetic disk. A magnetic disk pressing mechanism for a magnetic recording / reproducing apparatus, characterized in that an inclined surface having a uniform sectional shape in the circumferential direction is formed.