JP2674045B2 - Disk drive device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a disk drive device that rotationally drives a disk, and more particularly to a technique for positioning a turntable that holds a disk. [Summary of the Invention] The present invention is, for example, a chuck portion structure of a disk drive device having a turntable for holding a magnetic disk such as a 3.5-inch micro-floppy disk on its upper surface, wherein a shaft is fixedly provided at the center of the turntable. The shaft is rotatably supported by an oil-impregnated bearing mounted on a chassis, and is rotatably linked to a drive motor (driving source) mounted on the chassis on the outer peripheral side of the turntable via, for example, a timing belt. And a reference surface for positioning the turntable in the horizontal direction is formed on each of the lower surface of the turntable and the upper surface of the oil-impregnated bearing, while the lower side of the shaft and the lower surface of the oil-impregnated bearing are formed. And the shaft is pulled downward to push the turntable reference surface toward the reference surface side of the oil-impregnated bearing. By interposing the means, the turntable can be positioned in the horizontal direction to maintain high accuracy even if the bearing cost is significantly reduced, and the thickness of the chuck part in the vertical (height) direction can be maintained. The thickness of the disk drive device can be made significantly thinner so that the overall thickness of the disk drive device can be significantly reduced. [Prior Art] For example, there is known a disk drive device having a turntable for holding (chucking) a 3.5-inch micro-floppy disk (magnetic disk) of a disk cassette on the upper surface. This will be described in detail with reference to FIG. 3. Reference numeral 30 denotes a disk drive device, and chassis 31
The shaft 34 of the turntable 33 is rotatably supported by the cylindrical portion 32 formed in the above through a ball bearing 35 and an oil-impregnated bearing 36. On the upper surface of the turntable 33, a substantially C-shaped magnet 37 for attracting (magnetically adhering) the center core 52 of the magnetic disk 51 and an elastic force of a leaf spring 38 are urged to project upward, Engagement hole 52 of core 52
It has a drive pin 39 which engages with a and rotates the magnetic disk 51. These turntable 33, axis 34, magnet
The chuck portion 40 is composed of 37, the drive pin 39, and the like. Further, a drive motor 41 as a drive source for rotating the shaft 34 is connected to the lower part of the shaft 34 on the lower surface side of the chassis 31. The drive motor 41 includes a rotor 44 including a rotor yoke 42 and a rotor magnet 43 fixed to a lower portion of the shaft 34,
It is composed of a printed circuit board 45, a stator coil 46, and a stator 48 including a stator yoke 47, which are arranged at a predetermined distance from the lower surface of the chassis 31. Then, by attracting the center core 52 of the magnetic disk 51 to the turntable 33 and engaging the drive pin 39 into the engagement hole 52a of the center core 52, the magnetic disk 51 is held on the upper surface of the turntable 33, The turntable 33 is rotated via the shaft 34 by driving the drive motor 1. [Problems to be Solved by the Invention] In the disk drive device 30, the turntable 33 is used.
Since the shaft 34 and the drive motor 41 have a direct drive structure, the rotor magnet 43 is pulled downward by the magnetic force of the stator yoke 48, and the ball bearing 35 that receives the reaction force is indispensable. The ball bearing 35 prevents the axial deflection of the shaft 34 in the radial direction to position the turntable 33 in the horizontal direction.
However, there is a disadvantage in that it is more expensive than the above and the cost of the entire apparatus is high. Further, since the chuck portion 40 of the disk drive device 30 has the direct drive structure as described above,
The thickness in the vertical direction (indicated by t in the figure) is increased, and it is not possible to reduce the overall thickness of the device. Therefore, the present invention provides a chuck portion structure of a disk drive device that is low in cost and can reduce the thickness of the chuck portion in the vertical direction to further reduce the thickness of the entire device. [Means for Solving Problems] A chassis, an oil-impregnated bearing means mounted on the chassis and having an upper surface reference surface on an upper surface side, and a shaft which is to be borne by the oil-impregnated bearing means in a substantially central portion, A turntable having a lower surface reference surface on the lower surface side, and pressing means for urging the turntable downward, and pressing the turntable so that the lower surface reference surface and the upper surface reference surface are substantially parallel to each other. And drive means provided on the chassis for supplying a rotational drive force to the turntable, and transmission means provided on the turntable for transmitting the rotational drive force from the drive means. [Operation] The turntable that holds the disk on the upper surface, the chuck portion that is fixed to the center of the turntable, and the chuck that consists of a shaft and the like, and the drive source that rotates the shaft are separated from each other on the chassis and provided separately. Since the drive structure is used, the vertical thickness of the chuck portion is significantly reduced. Further, since the reference surface is formed on each of the lower surface of the turntable and the upper surface of the oil-impregnated bearing that rotatably supports the shaft, the turntable is positioned in the horizontal direction. Even if the cost of the bearing is significantly reduced, the turntable can be easily positioned in the horizontal direction, and the shaft rotates through the oil-impregnated bearing without any shaft runout. As a result, the cost and thickness of the entire disk drive device can be significantly reduced. Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In FIGS. 1 and 2, reference numeral 1 is a disk drive device, and a cylindrical boss 3 is fitted in the center of a stepped flat portion 2a of a chassis 2 thereof. The turntable 5 is attached to the oil-impregnated bearing 4 which is the oil-impregnated bearing means press-fitted into the boss 3.
The shaft 6 press-fitted and fixed in the central hole 5a is rotatably supported. The oil-impregnated bearing 4 is formed in a cylindrical shape having an inverted concave vertical section, and the shaft 6 is slidably supported in a hole 4b formed in an upper portion 4a thereof. Further, the oil-impregnated bearing 4 is attached to the chassis such that the entire upper surface 4d which is the lower surface reference surface of the oil-impregnated bearing 4 is parallel to the flat portion 2a of the chassis 2, and the upper surface 4d is the horizontal direction of the turntable 5. It is a reference plane for positioning. Here, the horizontal positioning of the turntable 5 means that the upper surface of the turntable 5 is attached in parallel to the flat portion 2a of the chassis 2, that is, when the disk drive device is horizontally mounted. That is, the upper surface of the turntable 5 is positioned horizontally. The turntable 5 is formed into a disc shape by a resin magnet, and a portion 5b around the shaft 6 on the upper surface thereof.
In addition, for example, a center core 52 fixed to a 3.5-inch micro floppy disk (magnetic disk) 51 of the disk cassette 50 is attracted by the magnetic force, placed and held. Then, in the substantially square engagement hole 5c formed near the shaft 6 of the turntable 5, an annular leaf spring 7 and a tension coil spring 8 partially fixed to the lower surface of the turntable 5 are interposed. A drive pin 9 biased upward is attached so as to be retractable. On the outer peripheral surface of the turntable 5, a rotation transmission body 10 which is a transmission means made of an annular resin is fixed by an adhesive or the like. A gear tooth-shaped small-diameter pulley portion 10a is integrally formed on the upper side of the outer peripheral surface of the rotation transmitting body 10, and a large-diameter gear (not shown) for meshing with an auto-ejecting gear is engaged on the lower side thereof. The part 10b is integrally formed. The position (height) of the small-diameter pulley portion 10a is located at substantially the same height as the position of the sliding portion between the hole 4b of the oil-impregnated bearing 4 and the shaft 6. Further, an upper surface reference surface 5d, which is a portion around the axis 6 on the lower surface of the turntable 5, is recessed from the remaining portion, and serves as a reference surface for positioning the turntable 5 in the horizontal direction. . To the reference surface 5d and the reference surface 4d of the oil-impregnated bearing 4, annular plate-shaped spacers 11 and 12 made of oil-impregnated material for preventing the turntable 5 and the oil-impregnated bearing 4 from being scraped are fixed, respectively. Since the spacers 11 and 12 slide against each other, the turntable 5 and the oil-impregnated bearing 4 do not directly slide, and their wear is prevented. That is, since there is no uneven wear, the horizontal positioning of the turntable 5 is always maintained with high accuracy. A lower portion of the shaft 6 is formed to have a small diameter, and a spring receiver 14 is fixed to the lower portion via a spacer 13. The oil-impregnated bearing 4 is provided between the annular plate-shaped washer 15 that abuts the lower surface of the upper portion 4a of the oil-impregnated bearing 4 and the collar 14a of the spring receiver 14.
That is, there is interposed a compression coil spring 16 which is a pressing means for pulling the turntable 5 downward so that the oil-impregnated bearing 4 and the spacers 11 and 12 of the turntable 5 are always in contact with each other. Due to this biasing force, the reference surface 5d of the turntable 5 follows the reference surface 4d of the oil-impregnated bearing 4 and is parallel thereto.
That is, the upper surface of the turntable 5 is the flat portion 2a of the chassis 2.
Is set in parallel with. The oil-impregnated bearing 4, the turntable 5, the shaft 6, the compression coil spring 16 and the like constitute a chuck portion 17 of the disk drive device 1. Further, a thin drive motor 18 which is a drive means is disposed at a position on the chassis 2 which is separated from the turntable 5 by a predetermined distance. A gear tooth-shaped drive pulley (not shown) fixed to a rotary shaft 19 of the drive motor 18 and the rotation transmission body.
Between the small-diameter pulley section 10a of 10 and the timing belt 20
Have been passed over. The timing belt 20 is stretched between the drive pulley and the small-diameter pulley portion 10a so as not to be loosened by adjusting the belt tension by the tension roller 21. This tension roller 21 is a pin on the chassis 2.
A plate-shaped tension arm rotatably supported by 22
It is rotatably supported at the tip of 23. A tension coil spring 24 is interposed between the base end portion of the tension arm 23 and the bracket portion 2b erected on the chassis 2, and the tip end portion of the tension arm 23 is constantly moved to the turntable 5 side. A predetermined tension is applied to the timing belt 20 by the tension roller 21. In FIG. 1, reference numeral 25 is a positioning pin for positioning when the disc cassette 50 is attached, and 26 is a recording / recording pin on the disc 51.
A magnetic head for reproduction. The magnetic head 26 is mounted on a head carrier (not shown) that reciprocates on the turntable 5 side on the chassis 2. According to the disk drive device 1 of the above-described embodiment, the chuck portion 17 that holds and rotates the disk 51 is provided with the drive motor 18 that is a drive source thereof to form an indirect drive structure. Compared to
The thickness (t) in the height (vertical) direction of the chuck portion 17 can be remarkably reduced. As a result, the overall thickness of the disk drive device 1 can be greatly reduced. Further, the reference surface 5d of the turntable 5 of the chuck portion 17 and the reference surface 4d of the oil-impregnated bearing 4 rotatably supporting the shaft 6 of the turntable 5 are brought into contact with each other via the spacers 11 and 12, and Since the shaft 6 is pulled downward by the tensile force of the tension coil spring 16 so that the spacers 11 and 12 are always in contact with each other, the horizontal positioning (flatness) of the turntable 5 is the same as that of the oil-impregnated bearing 4. It is possible to always output with high accuracy following the reference surface 4d. Since the oil-impregnated bearing 4 is less expensive than the conventional ball bearing, the cost can be significantly reduced. Further, the height of the small-diameter pulley portion 10a that transmits the driving force of the drive motor 18 to the turntable 5 via the timing belt 20 is substantially the same as the height of the contact and sliding portions of the shaft 6 and the oil-impregnated bearing 4. Therefore, the moment due to the lateral pressure of the timing belt 20 does not act on the shaft 6 of the turntable 5,
The shaft 6 does not tilt in the radial direction of the turntable 5 when the turntable 5 rotates,
At the time of rotation, the play of the shaft 6 in the radial direction can be prevented, and the rotational runout can be reliably prevented. When the turntable 5 is rotated, the spacer 13 and the spacer 13 are received together with the shaft 6.
14, the washer 15 and the compression coil spring 16 rotate together. Further, since the oil-impregnated bearing 4 is press-fitted and fitted into the boss 3, the height of the upper surface 5b of the turntable 5 and the magnetic head 26 are fixed.
Even if the drive structure is such that the height difference between the two does not reach a predetermined value, the upper surface 5b of the turntable 5 is pushed downward as shown by the arrow in FIG. 1, or the lower part of the oil-impregnated bearing 4 is shown by the arrow in FIG. It is possible to easily redo the height adjustment by pushing it upwards. At this time, the adjustment work can be performed more easily by forming, for example, three holes for adjustment work in the upper surface 5b of the turntable 5 in advance. According to the above-described embodiment, the turntable 5 is rotated by using the timing belt 20. A small-diameter gear portion is formed above the rotation transmission body 10 of the turntable 5 and is driven via an intermediate gear or the like. The turntable 5 may be rotated by gear driving by engaging with a gear provided on the shaft of the motor. Also, without interposing the spacers 11 and 12,
Both the oil-impregnated bearing 4 and the reference surfaces 4d, 5d of the turntable 5 may be brought into direct contact with each other and slid. Further, it goes without saying that the biasing means for pulling the shaft 6 downward is not limited to the compression coil spring. [Effects of the Invention] As described above, according to the present invention, a turntable for holding a disc on the upper surface of the chuck portion of the disc drive device, a shaft fixed to the center of the turntable, and the turntable are provided. Since the drive source to be rotated is separated from the chassis and provided separately, the vertical thickness of the chuck portion can be significantly reduced. Further, a reference surface for positioning the turntable in the horizontal direction is formed on the lower surface side of the turntable and the upper surface side of the oil-impregnated bearing that rotatably supports a shaft fixed in the center of the turntable, respectively. Since the biasing means for pressing the reference surface of the turntable to the reference surface side of the oil-impregnated bearing is interposed between the lower side of these shafts and the lower surface side of the oil-impregnated bearing,
With the oil-impregnated bearing, even if the cost of the bearing is significantly reduced, the turntable can be easily and reliably positioned in the horizontal direction, and the precision can be maintained with high precision. Therefore, the cost and thickness of the entire disk drive device can be significantly reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a chuck structure of a disk drive device showing an embodiment of the present invention, FIG. 2 is a perspective view of the same, and FIG.
FIG. 1 is a sectional view of a chuck portion structure of a conventional disk drive device. 1 ... Disk drive device, 4 ... Oil-bearing bearing (oil-bearing means), 5 ... Turntable, 5b ... Top surface, 4d ...
Reference surface (lower surface reference surface), 5d ... Reference surface (upper surface reference surface),
6 ... Shaft, 10 ... Rotation transmission body (transmission means), 16 ... Compression coil spring (pressing means), 17 ... Chuck portion, 18 ... Drive source (driving means), 51 ... Disk.

Claims (1)

(57) [Claims] A turntable having a chassis, an oil-impregnated bearing means mounted on the chassis and having an upper surface reference surface on an upper surface side, a shaft supported by the oil-impregnated bearing means in a substantially central portion, and having a lower surface reference surface on a lower surface side. And a pressing means for urging the turntable downward and pressing the turntable so that the lower surface reference surface and the upper surface reference surface are substantially parallel to each other. A disk drive device comprising: a drive unit that supplies a rotary drive force to the table; and a transmission unit that is provided on the turntable and that transmits the rotary drive force from the drive unit.