JPS62146462A - Magnetic disk pressing mechanism for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent a magnetic disk from being damaged due to a stabilizing plate by forming the outside from almost the center of the pressing surface of the stabilizing plate in the radius direction of the magnetic disk as a plane almost parallel with the magnetic disk and the inside as an inclined surface in the separating direction from the magnetic disk. CONSTITUTION:When the magnetic disk 11 is supported by a center hub 13 and rotated by a spindle motor 12, the largest floating height h0 is obtained on the center part in the radius direction of the magnetic disk 11 by an air flow due to the rotation of the magnetic disk 11 and the floating height on the most outside and inside parts of the stabilizing plate 15 is reduced lower than the value h0, but the plate 15 is not contacted with the magnetic disk 11. Namely, the plate 15 has an inclined surface 15c on its inside and the maximum receded value (d) from a plane 15b is set up to a value slightly smaller than the deflection of the magnetic disk 11 which is generated close to the most inner periphery of the plate 15 and has a finite size, so that the floating of the magnetic disk 11 can be secured on the most inside part of the plate 15. Namely, the magnetic disk 11 is not contacted with the plate 15 at the rotation of the magnetic disk 11.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a magnetic recording and reproducing apparatus for recording and reproducing data on and from a flexible magnetic disk, and more particularly to a magnetic disk pressing mechanism that presses a magnetic disk against a magnetic head.

"Prior Art and its Problems" In the camera field, this type of magnetic recording/reproducing device is used in electronic still cameras that convert video signals into electrical signals and store them. In this device, in order to ensure that the magnetic disk comes into contact with the magnetic head, a stabilizing plate is located on the opposite side of the magnetic head, and the stabilizing plate presses the magnetic disk against the magnetic head. This stabilizing plate has a type that directly presses the back of the magnetic head, and a part that corresponds to the magnetic head is a concave part, and by pushing the magnetic disk on the side edge of the back of the magnetic head, it utilizes the bending rigidity of the disk. An indirect press type is known in which this is brought into contact with a magnetic disk, and in electronic still cameras,
The latter indirect press type is used.

4 to 9 are diagrams for explaining the structure and problems of this conventional indirect press type. As shown in FIGS. 4 and 5, the support hole 11a at the center of the magnetic disk 11 is connected to the center hub 11 of the spindle motor
It is supported by and rotates. A magnetic head 14 and a stabilizing plate 15 are located on the front and back sides of the magnetic disk 11.
corresponds to the moving direction of the magnetic head 14. A recess 16 is formed oriented in the radial direction of the magnetic disk 11.

The tip of the stabilizer plate 15 in the radial direction of the magnetic disk is a pressing surface 17 that contacts the magnetic disk 11. This pressing surface 17 suppresses vibrations when the magnetic disk 11 runs (rotates), and acts on each track. The magnetic head 14 is brought into stable contact.

The above magnetic recording/reproducing device, as shown exaggerated in the figure,
The magnetic disk pressing surface 15a of the stabilizing plate 15 is brought into contact with the magnetic disk ll to bend the magnetic disk 11 into the four parts 16, and its rigidity causes the magnetic disk 11 to be pressed against the magnetic head 1.
At this time, the upper surface of the magnetic disk 11 supported by the spindle motor 12 near the support hole 11a and the magnetic disk 11 of the stabilizing plate 15 are
When a gap A is created between the contact surface with the magnetic disk pressing surface 15a, the dimension B from the lower end 13a of the center hub 13 to the second surface of the magnetic disk 11 has a certain tolerance due to different magnetic disks 11. When this occurs, the following problems arise. FIG. 6 shows the dimensional variation due to the tolerance of the magnetic disk 11 in terms of ±B'.
Even if the dimensions are determined to be, if the above-mentioned dimension B is different, when the magnetic disk 11 is considered as a double-supported beam, the height of one of the fulcrums will not be constant as shown by ±B'. Then, the contact pressure between the magnetic disk 14 and the magnetic disk 11 becomes inconsistent, and the contact becomes unstable.

Therefore, as shown in FIGS. 7 and 8, the spindle motor 12 is slightly raised relative to the magnetic head 14 and the stabilizer plate 15, and the dimension B of the upper surface of the magnetic disk 11 from the lower surface 13a of the center hub 13 is -B' An apparatus has been proposed in which the size of the upper surface of the magnetic disk 11 from the magnetic disk pressing surface 15a of the stabilizing plate 15 can be ensured 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) goes up and down, the outermost part of the stabilizer plate 15 Support points 17s and 18s are formed on the holding surface 17 and the innermost portion 18, respectively. Therefore, the deflection iE of the magnetic disk 11 due to the two fulcrums 17s, 18s and the magnetic head 14 is constant regardless of the type of the magnetic disk 11, so the problem of unstable contact pressure is avoided.

However, in this device, the following problem arises. FIG. 9 is a sectional view taken along line IX-IX in FIG. 4, and when the magnetic disk 11 rotates, between the holding surface (outermost part) 17 and the innermost part 18 of the stabilizer plate 15, It floats relative to the magnetic helad 14. However, presser surface 17
In the innermost portion 18, the flying height of the magnetic disk 11 with respect to the magnetic head 14 becomes small due to lateral leakage of airflow. That is, even if a flying height of ha can be secured at the radial center of the magnetic disk 11, the holding surface 17
and in the innermost part 18, hl and h2, respectively.
can only secure a floating height of . In particular, the magnetic disk 11 near the innermost part 18 of the stabilizer 15 tends to move away from the stabilizer 15 due to floating near the center in the radial direction, but the bending rigidity of the magnetic disk 11 itself cancels this, so the overall The floating height cannot be secured. In particular, in this part, the contact between the magnetic disk 11 and the stabilizer 15 is close to a line contact or a point contact, which causes scratches on the magnetic disk 11 and the stabilizer 15, which causes frequency jitter in the recording/reproduction signal. This may cause

OBJECTS OF THE INVENTION The present invention aims to solve the above-mentioned problems with conventional magnetic recording and reproducing devices, and to provide a device in which the stabilizer plate does not damage the magnetic disk.

``Summary of the Invention'' The present invention was made based on the fact that the entire pressing surface of a conventional stabilizer in the radial direction of the magnetic disk is a plane parallel to the magnetic disk. The disc pressing surface is characterized in that the outer side of the approximate center is a plane substantially parallel to the magnetic disk, and the inner side is an inclined plane in the direction away from the magnetic disk.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. Figure 1 shows
This shows an embodiment of the present invention, and the same parts as the conventional device are given the same reference numerals.The magnetic disk pressing surface 15a of the stabilizing plate 15 according to the present invention is different from the conventional device. The outer side of the approximate center in the radial direction is a plane 15b parallel to the magnetic disk 11, and the inner side thereof is an inclined plane 15c in the direction away from the magnetic disk. Plane 15b
As in the apparatus shown in FIG. 7, the positions of the magnetic disks 11 and 11 are set so as to ensure the size of the upper surface of the magnetic disk 11 from the plane 15b. On the other hand, the maximum amount of retraction from this plane 15b due to the inclination of the inclined surface 15c (the magnetic disk 11
The length d in the direction away from the stabilizer plate 15 is smaller than the amount of displacement near the innermost portion 18 due to the deflection of the floating magnetic disk near the center of the stabilizer plate 15, and is a finite amount.

The device with the above configuration has a magnetic disk 1 in the center hub 13.
When the magnetic disk 1 is supported and rotated by the spindle motor 12, the airflow caused by the rotation of the magnetic disk 11 provides the largest flying height ho at the center in the radial direction, and the maximum flying height ho of the stabilizer plate 15 is obtained. 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 plate 15 do not come into contact with each other. The reason will be explained with reference to FIGS. 2 and 3.

Figure 2 shows a model of the deformation of the magnetic disk 11 by considering it as a beam.The right end of the figure is the center hub 1.
Stabilizer plate 1 is regarded as a fixed end for 3 and indicates the maximum flying height.
5 is pushed down with a force P. Here, the amount of deflection is D+ho, which is the amount of deflection pushed down by the flat surface 15c of the stabilizer 15 and the amount of floating ha.
The force P is a floating blade caused by the air flow accompanying the rotation of the magnetic disk 11. Although Naori P is actually not a concentrated load but a mountain-shaped distributed load, it is treated as a concentrated load for convenience. Furthermore, Q in the figure indicates the protrusion force of the magnetic head when the magnetic helad 14 is located outside the stabilizing plate 15, that is, when it is located on a track near the outer periphery. The amount of deflection 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, but when it is rotating, the flying height increases as shown by the broken line.

is added to obtain Echo. The amount of deformation of the magnetic disk 11 gradually decreases from the point of action of P until it reaches the center hub 13.

On the other hand, when the magnetic head 14 is located closer to the center hub 13 than near the center of the stabilizer, as shown in FIG.
As shown by the broken line, the magnetic disk 11 is also an Echo disk.
The amount of deflection is as follows. This amount of deflection is the amount relative to the point at which P is applied, and as described above, the magnetic disk 11 is inclined up to the portion supported by the center hub 13. Therefore, the actual amount of protrusion of the magnetic head 14 with respect to the magnetic disk 11 must be determined by subtracting the difference δ in the amount of deflection at point Q due to the force P, that is, the amount is calculated as Echo-δ
becomes. Therefore, the ejection force Q of the magnetic helad 14 against the magnetic disk 11 in FIG. 3 is different from that in FIG. 2. However, the magnetic disk 11 has a disk shape, and the bending rigidity increases toward the center, and the same protrusion force can be produced even with a small amount of deflection.

To prevent such deformation of the magnetic disk 11, the stabilizing plate 15
has an inclined surface 15c on its inner side, and the maximum retraction id from the flat surface 15b is set to be slightly smaller than the amount of deflection near the innermost circumference of the stabilizer plate 15 among the deflections of the magnetic disk, and is finite. Therefore, the floating of the magnetic disk 11 on the innermost portion 18 of the stabilizer plate 15 can be ensured. In other words, when the magnetic disk 11 rotates, this stabilizer plate 1
No contact with 5.

"Effects of the Invention" As described above, the present invention provides a magnetic recording/reproducing device in which the inside of the magnetic disk pressing surface, approximately at the center in the radial direction of the magnetic disk, is an inclined surface in the direction away from the magnetic disk. Its inside does not come into contact with the stabilizer during rotation. Therefore, it is possible to prevent the occurrence of scratches on the inner and outer peripheral portions of the magnetic disk due to the stabilizing plate, and to prevent frequency jitter.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the magnetic disk pressing mechanism of the magnetic recording/reproducing apparatus according to the present invention, and FIGS. 2 and 3 are models showing deformation of the magnetic disk by the pressing mechanism according to the present invention, respectively. 4 shows an example of a conventional magnetic disk pressing mechanism. FIG. 5 is a cross-sectional view taken along the line ■-IV in FIG. 5. FIG. 5 is a cross-sectional view taken along the v-v line in FIG. 4. FIG. is a skeleton diagram for explaining the problems in the conventional device 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. A skeleton diagram showing the state of deformation of the magnetic disk in the device,
FIG. 9 shows the I of FIG. 5, which explains the problem with the device of FIG. 7.
It is a sectional view along the X-IX line. 11...Magnetic disk, 12...Spindle motor, 13...Center hub, 14...Magnetic head. 15... Stabilizer plate, 15a... Magnetic disk pressing surface,
15b...Flat surface, 15c...Slope surface, 16...Recessed portion, 17... Pressing surface (outermost part), 18... Innermost part. Patent applicant Asahi Optical Co., Ltd. Agent Kunio Miura Shigeru Matsui 5a Figure 1 Figure 2 Figure 3 Figure 5 Figure 6

Claims (1)

[Claims] (1) On the front and back sides of a flexible magnetic disk, a magnetic head for recording and reproducing data on the magnetic disk and a stabilizing plate having a concave portion in the corresponding part of the magnetic head are arranged, and the stabilizing plate allows the magnetic disk to be In a magnetic disk pressing mechanism of a magnetic recording/reproducing device that is brought into pressure contact with a magnetic head, of the pressing surface of the stabilizing plate facing in the magnetic disk radial direction, the outer side from the approximate center is a plane substantially parallel to the magnetic disk, and the inner side is a flat surface that is substantially parallel to the magnetic disk. 1. A magnetic disk pressing mechanism for a magnetic recording/reproducing device, characterized by having an inclined surface in a direction away from the magnetic disk.