JP2001229661A - Disk drive assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the reliability of a disk drive assembly by preventing the floating of a disk when the disk rotates with this device and solving the problem of the contact of the members within the device and the deviation of the servo in a pickup and to reduce the cost of products by remedying such problem with a slight change of the device shape. SOLUTION: The member existing atop the disk when the disk is mounted is provided with projecting parts radial to the center of rotation of a spindle motor on the surface facing the disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive for reproducing or recording information by rotating a disk-shaped disk as a recording medium, and more particularly to a CD-ROM, DVD-RO.
The present invention relates to a slim-type disk drive for M, DVD-RAM, and the like.

[0002]

2. Description of the Related Art When a disk (hereinafter, simply referred to as a "disk") serving as a recording medium rotates in a disk drive, a pressure difference is generated between the disk and the upper and lower sides due to the flow of air above and below the disk, and the disk floats to chuck the disk. There is such a problem that the king portion contacts the member on the upper surface of the disk (hereinafter, the upper member is referred to as a “top cover” and the lower member is referred to as a “tray”). In addition, there is a problem that the servo is disengaged because the flying height of the disk exceeds the tracking range of the pickup. Especially in a slim disk drive, the pressure on the lower surface of the disk (tray side) is close to the atmospheric pressure,
There is a problem that the upper surface of the disk (top cover side) tends to be lower than the atmospheric pressure, and the disk easily floats.

[0003] As a conventional technique for preventing an adverse effect of air on a disk device due to rotation of the disk up and down, there is one disclosed in Japanese Patent Application Laid-Open No. H11-126470. In this publication, an air vent hole is provided in a mounting surface portion of a tray to release air interposed between a disk and a tray on which the disk is mounted, thereby suppressing vibration generated in the disk.

[0004]

However, the above technique is
It is effective to prevent the vibration that occurs on the disc,
It is impossible to prevent the disk from flying. The reason for this is that the pressure difference between the upper and lower sides of the disk does not change even if holes are provided on the tray side and air is escaped because the lower surface of the disk (the tray side) is close to the atmospheric pressure, and the floating of the disk cannot be prevented.

The present invention prevents a disk from floating when the disk rotates in a disk drive,
It is an object of the present invention to solve the problem that the servo is disengaged in the contact between the members inside the apparatus and the pickup, to improve the reliability of the apparatus, and to suppress an increase in the number of manufacturing processes of the product.

[0006]

An object of the present invention is to provide a disk drive in which a disk (top cover), which is located on a surface opposite to the spindle motor when the disk is mounted, faces the disk facing the disk. This is achieved by providing a radial projection with respect to the center.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an exploded perspective view of a disk drive and a disk 1 serving as a recording medium. In the disk drive device, a disk 1 which is a disk-shaped recording medium is placed on a tray 2, transported inside the device, and attached to a turntable 4 installed on a rotating shaft of a spindle motor 3. The spindle motor 3 is installed on the unit mechanical chassis 5,
The unit mechanical chassis 5 is supported by an insulator 6. The unit mechanism chassis is provided with a pickup 7 for reproducing or recording / reproducing information on the disk 1. The unit mechanical chassis is installed on a mechanical base 8 serving as a frame of the disk drive. Inside the disk drive, a top cover 9 facing the disk surface, which is a member of the disk 1 opposite to the side on which the spindle motor is mounted.
, The bottom cover 10 and the front panel 11 form a closed structure.

In this embodiment, since the disk 1 rotates and the pressure on the upper surface becomes lower than the lower surface of the disk due to the flow of air up and down, the members such as the chucking portion 12 for floating the disk and clamping the disk are formed. This solves the problem that the servo comes off because the disk comes into contact with the top cover 9 or the flying height of the disk exceeds the tracking range of the pickup 7. The tendency is that if the height of the disk device itself (main body case) is reduced and a thin disk device is formed, the distance between the top cover and the disk becomes small, and the problem of floating of the disk becomes conspicuous. The configuration and operation of the specific countermeasures will be described below.

FIG. 2A shows the shape of the top cover when the top cover 9 is viewed from the direction of the arrow A (the disk side) in FIG. The feature of this embodiment is that a projection 13 is provided on the surface of the top cover 9 facing the disk 1 so as to generate a pressing force from the top cover side toward the disk. The circle 12 indicated by a dotted line in the figure indicates the area occupied by the disk, and the protrusion 13 is 0.34 × R0 when the distance from the rotation center of the spindle motor is R and the disk radius is R0.
It is provided in an annular region in the range of <R <R0. Fig. 2 (b)
2 shows a cross section DD of FIG. 2A. The height h of the protrusion is h> 0.1 with respect to the gap h0 between the disc and the top cover.
It is made to be 4 × h0.

Next, a description will be given of the pressing effect by the air flow when the configuration of this embodiment is adopted, with reference to FIGS. 3, 4 and 5. FIG. 3 (a) and 3 (b) show the flow of air in a cross section along the arrow B in FIG. FIG. 3A shows the protrusion 13.
FIG. 3B shows a flow in the case where a common top cover shape having no projection is provided, and FIG. 3B shows a flow in a case where the protrusion 13 of the present invention is provided.

As described above, in a thin disk device, the lower surface of the disk (tray side) is close to the atmospheric pressure, and the upper surface of the disk (top cover side) is lower than the atmospheric pressure, which may cause a problem that the disk floats. . By providing the protruding portion 13 as shown in FIG. 3B, when the air flow hits the protruding portion 13, the air flow is disturbed, whereby the kinetic energy of the air flow is converted into pressure, and the air flow is converted into the pressure at the portion C in the drawing. The pressure will increase. When the pressure increases in the portion C, a force for pushing the disk downward is generated on the disk surface, so that the disk can be prevented from floating.

FIG. 4 shows a comparison of the disk flying height between the present invention and a normal top cover shape (conventional shape). The horizontal axis in the figure represents the number of rotations, and the vertical axis represents the flying height of the disk. As shown in FIG. 4, in the conventional top cover surface shape, the flying height of the disk rapidly increases with an increase in the number of revolutions. However, when the projection is provided as in the present invention, the flying height is slightly increased. Can be held down.

FIG. 5 shows the shape of the protrusion of the present invention, in which the horizontal axis represents the height h of the protrusion and the vertical axis represents the relative flying height. The three lines in FIG. 5 represent the relative flying height (the value obtained by dividing the flying height in the present invention by the flying height of a general top cover disk) when the length L of the protrusion is changed. It is a thing. Here, the length of L is a value when the outermost peripheral portion of the disk is extended in the center axis direction with the zero point as the zero point.

When a disk having a disk radius of about 60 mm is considered, the length L of the protruding portion is 10 mm (from the disk radius of FIG. 5).
It can be seen that the effect cannot be obtained unless it is 16% or more. It is considered that the effect is obtained when the length L is about 30 mm (50% of the disk radius), and that the sufficient effect is obtained when the length L is 40 mm (66% of the disk radius). Further, the effect is obtained as the protruding portion is disposed closer to the outer periphery of the disk. The reason for this is that the closer to the outer periphery of the disk, the higher the circumferential velocity of the air on the upper surface of the disk, and the greater the pressure rise when colliding with the protrusion. For these reasons, in the present invention, the mounting position of the protruding portion with respect to the top cover depends on the distance from the rotation center of the spindle motor to R,
When the disk radius is R0, 0.34 × R0 <R <R0
In the annular area. On the other hand, the height h of the protruding portion must be not less than 0.2 mm (14% of the gap between the disk and the top cover) as shown in FIG. 5 to obtain the effect of reducing the flying height. For this reason, in the present invention, the height h of the protruding portion is determined by the gap between the disk and the disk upper surface (top cover).
The shape was such that h> 0.14 × h0 with respect to h0.

The width of the protruding portion in the circumferential direction of the disk is more effective at 10 mm than at 5 mm. Further, the number of protrusions is required to be at least three or more in order to prevent the high-pressure portions generated in the protrusions from becoming non-uniform in the disk surface, and the arrangement of the protrusions is generally about the circumference of the disk from the viewpoint of equalizing the high-pressure portions. They need to be arranged at substantially equal intervals in the direction. Further, in the present embodiment, a disk having a radius of 60 mm has been described. However, even if the radius changes, the length and height of the substantially protruding portion may be provided in proportion.

The projections provided on the top cover described above can be easily realized only by sticking a seal on the top cover. Further, even members other than the seal can be easily realized simply by sticking them to the top cover. Apart from these methods, by integrally forming the projection on the top cover, the projection can be easily formed at low cost. For example, when a metal such as aluminum is used for the top cover, the protruding portion can be easily formed by deep drawing. In addition, when a resinous material such as plastic is used, it is possible to easily perform integral molding simply by adding a shape corresponding to the protruding portion to the mold.

[0018]

According to the present invention, with respect to a member located on the upper surface of the disk when the disk is mounted, a radial projection is provided on the surface facing the disk with respect to the rotation center of the spindle motor.
By utilizing the fact that the air flow on the upper surface of the disk collides with the protrusion and the pressure on the upper surface of the disk increases, it is possible to prevent the disk from floating due to the pressure difference between the upper and lower surfaces of the disk.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a disk drive device and an external view of a disk serving as a recording medium.

FIG. 2 is a top cover shape of the present invention viewed from the direction of arrow A in FIG.

FIG. 3 shows air flow in a normal top cover shape and a top cover shape of the present invention.

FIG. 4 shows a flying height of a disk with respect to a disk rotation speed.

FIG. 5 shows the relative flying height of the disk with respect to the height and length of the protrusion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disc, 2 ... Tray, 3 ... Spindle motor, 4
... turntable, 5 ... unit mechanical chassis, 6 ... insulator, 7 ... pickup, 8 ... mechanical base, 9 ...
Top cover, 10 ... Bottom cover, 11 ... Front panel, 12 ... Chucking, 13 ... Protrusion

Continued on the front page (72) Inventor Yoshihiro Sato 502, Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratories, Hitachi, Ltd. (72) Inventor Yoshiaki Yamauchi 502-Kindachi-cho, Tsuchiura-shi, Ibaraki Pref. (72) Inventor Seiichi Kato 502 Kandachi-cho, Tsuchiura-city, Ibaraki Pref., Machinery Research Laboratory, Hitachi, Ltd. (72) Inventor Shinya Tsubota 1410, Inada, Hitachinaka-shi, Ibaraki Pref. Digital Media Product Division, Hitachi, Ltd. 72) Inventor Mitsuo Satake 1 Kitano, Majo, Mizusawa-shi, Iwate F-term in Hitachi Media Electronics Co., Ltd. 5D038 BA04 CA14 GA04

Claims (4)

[Claims] When a disk is mounted on a spindle motor, a plurality of members radially from a rotation center of the spindle motor are provided on a member facing a surface of the disk opposite to the spindle motor, excluding a member for clamping the disk. A disk drive device provided with a protrusion. 2. The disk device according to claim 1, wherein the protrusion is 0.34 × R0 <R <, where R is the distance from the rotation center of the spindle motor and R0 is the disk radius.
A disk drive device provided in an annular region in the range of R0, wherein the height h of the protrusion is such that h> 0.14 × h0 with respect to a gap h0 between the disk and the disk upper surface. 3. The disk drive according to claim 1, wherein said projection is formed by attaching a tape or another member. 4. The disk drive according to claim 1, wherein said projection is formed integrally with said member.