JPH0544919Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a disc turntable in which a disc is magnetically chucked onto the turntable body.

[Summary of the idea]

The present invention is a disc turntable in which the disc is chucked onto the turntable body by the magnetic attraction force of the magnet, and an elastic body is installed between the recess of the turntable body and the magnet. By pushing the magnet into the recess against the elastic body up to a predetermined distance from the disc mounting surface of the main body, and gluing this magnet to the turntable main body, the disc mounting surface of the turntable main body and the magnet can be connected. This makes it possible to ensure distance accuracy extremely accurately and easily.

[Conventional technology]

As is well known, some disk devices in which recording/reproducing disks can be selectively exchanged chuck the disk onto the turntable body using the magnetic attraction force of a magnet.

An example of this type of disc turntable will be explained with reference to FIG. That is, the turntable body 2 is fixed to the upper end of the motor spindle 1. The upper surface of this turntable main body 2 is a disk mounting surface 3, and a recess 4 is provided inside this disk mounting surface 3. A magnet 5 is bonded onto the bottom surface 4a of the recess with an adhesive. Here, a predetermined distance _h1 is set between the disk mounting surface 3 of the turntable body 2 and the magnet upper surface 5a.

Next, when the disk 7 is mounted on the turntable main body 2, the center hole 8 of the disk 7 is inserted into the tip of the motor spindle 1, and the disk 7 is brought into contact with the disk mounting surface 3. A yoke 9 made of a magnetic material attached to the central lower surface of the disk 7 is attracted by the magnetic attraction force of the magnet 5, and the disk 7 is chucked. In this state, the disk 7 is rotationally driven by the turntable main body 2 which is rotationally driven together with the motor spindle 1, and recording and reproduction are performed on the disk 7 by a recording/reproducing head (not shown). .

[Problem that the invention attempts to solve]

By the way, when the disk 7 is chucked by the magnetic attraction force of the magnet 5 as described above, the distance _h1 between the disk mounting surface 3 of the turntable body 2 and the upper surface 5a of the magnet is large or small. There will be a difference in chucking power. If the distance h ₁ is large and the chucking force is weak, the disc 7 will slip against the turntable body 2 when the disc 7 is rotated, and conversely, if the distance h ₁ is small and the chucking force is strong, the disc 7 will slip when unloading. In this case, a large amount of force is required to remove the disc 7 from the turntable main body 2.

Therefore, in order to set the distance h ₁ with high precision, it has been conventionally known that the distance h ₂ between the disk mounting surface 3 of the turntable body 2 and the bottom surface 4a of the recess (that is, the depth of the recess 4), and the distance h 2 of the magnet 5 are set with high accuracy. Sufficient attention was paid to the thickness h ₃ and the removal of dust and the like between the bottom surface 4a of the recess and the magnet 5 during bonding. Therefore, the processing and assembly of the turntable body 2, magnet 5, etc. must be performed with extremely high precision, and it is extremely difficult to remove dust such as magnetic powder that has adhered to the magnet 5, which has been magnetized in advance. . These factors have caused various losses such as decreased productivity during mass production.

Therefore, the present invention makes it possible to ensure the accuracy of the distance between the disk mounting surface of the turntable body and the magnet extremely accurately and easily.

[Means for solving problems]

The present invention consists of a turntable body having a disk mounting surface for receiving a disk, a chucking magnet installed in a recess provided in the turntable body, and an elastic body installed between the magnet and the recess. pushing the magnet into the recessed portion against the elastic body up to a predetermined distance against the disk mounting surface;
This magnet is bonded to the turntable body.

[Effect]

According to the present invention, the magnet is pushed into the recess against the elastic body to a predetermined distance with respect to the disk mounting surface of the turntable body, and this magnet is adhered to the turntable body, so that the disc of the turntable body can be attached. The distance accuracy between the disk mounting surface and the bottom of the recess, the thickness accuracy of the magnet, and the dust between the bottom of the recess and the magnet do not affect the distance accuracy between the disk mounting surface and the magnet. Accuracy can be ensured extremely accurately. The above distance can be set extremely easily from the disk mounting surface side using, for example, a step jig.

〔Example〕

An embodiment of a disc turntable to which the present invention is applied will be described below with reference to FIGS. 1 and 2.

First, as shown in FIG. 2, a circular turntable body 22 made of a magnetic material is fixed to the upper end of a motor spindle 21. As shown in FIG. The outer periphery of the upper surface of the turntable main body 22 is an annular flat disk mounting surface 23, and a circular recess 24 is provided inside the disk mounting surface 23. A ring-shaped magnet 25 is installed in the recess 24, and an elastic body 26 is installed between the magnet 25 and the bottom surface 24a of the recess. In addition, as shown in FIG. 1, the depth of the recess 24
_h4 is sufficiently deeper than the thickness _h5 of the magnet 25. Further, in this embodiment, a disc spring is used as the elastic body 26. An adhesive 27 is filled between the magnet 25 and the recess 24, and the magnet 25 is bonded to the turntable body 22.

That is, when bonding the magnet 25, the first
As shown in the figure, first, the elastic body 26 and the magnet 25 are housed in the recess 24 of the turntable body 2. Then, the magnet 25 is pushed in from above in the direction of the arrow a against the elasticity of the elastic body 26 using the ring-shaped step jig 30. This step jig 30 is a step gauge having an annular flat reference surface 31 and a pressing surface 32, and the distance h ₆ (for example, 0.1 mm) between these reference surfaces 31 and pressing surfaces 32 is extremely high. Formed with precision. Then, the pressing surface 32 of the step jig 30 presses the upper surface 25a of the magnet to bring the reference surface 32 into contact with the disk mounting surface 23. In this state, the turntable body 22
An adhesive 27 is filled between the magnet 25 and the recess 24 through an injection hole 28 provided in the turntable body 22, and the magnet 25 and the elastic body 26 are bonded to the turntable body 22. In this example, the adhesive 27
For example, a magnetic epoxy adhesive mixed with barium ferrite powder is used.

As described above, by bonding the magnet 25 to the turntable main body 22, the distance _h7 between the disk mounting surface 23 of the turntable main body 22 and the magnet upper surface 25a becomes equal to the reference surface of the step jig 30. 31 and the pressing surface 32, which corresponds to the distance _h6 , is set with extremely high precision. Therefore, the distance h ₄ between the disk mounting surface 23 and the recess bottom surface 24a
(that is, the depth of the recess 24) and the thickness _h5 of the magnet 25 do not affect the distance _h7 , and the influence of dust and the like between the bottom surface 24a of the recess and the magnet 25 can also be prevented.

In addition, in FIG. 2, the turntable main body 2
The motor spindle 21 to which the motor spindle 2 is fixed is rotatably supported by a motor base 34 via a pair of upper and lower bearings 35. and a rotor magnet 36 attached to the lower end of the motor spindle 21.
A motor 38 is constituted by the stator coil 37 and the stator coil 37 provided on the lower surface of the motor base 34.

Next, as shown in FIG. 2, the disk 40 mounted on the turntable body 22 is rotatably housed in a cartridge 43 consisting of upper and lower halves 41 and 42 made of synthetic resin or the like. It is something. This disk 40 is called an SSR disk, and has a pair of upper and lower magnetic sheets 45, which are sheet-like recording media, attached to the upper and lower sides of a disk substrate 44 made of synthetic resin, light metal, etc., with initial tension applied. It is something. A center core 47 having a center hole 46 is integrally molded in the center of the disk substrate 44, and a disk-shaped yoke 48 made of a magnetic material such as a stainless steel plate is attached to the lower surface of the center core 47. There is. A circular turntable insertion hole 49 is provided at approximately the center of the lower half 42, facing the center core 47.

Then, when the cartridge 43 is lowered from above, the turntable body 22 is relatively inserted into the turntable insertion hole 49 from below, and the center hole 46 of the disk 40 is inserted into the motor spindle 21.
At the same time, the center core 47 of the disk 40 is brought into contact with the disk mounting surface 43 of the turntable main body 22. and yoke 48
is attracted by the magnetic attraction force of the magnet 25, and the disk 40 is chucked. In this chucking state, the disk 40 is rotationally driven by the turntable main body 22 which is rotationally driven integrally with the motor spindle 21, and the upper and lower pairs of the disk 40 are rotated by a pair of upper and lower magnetic heads (not shown). The magnetic sheet 45 is selectively recorded and reproduced.

At this time, since the distance _h7 between the disk mounting surface 23 and the magnet upper surface 25a is set with high precision as described above, the chucking force by the magnet 25 is at an optimal value. Therefore, there is no possibility that the disc 40 slips against the turntable main body 22 when it is rotationally driven, or that a large amount of force is required when removing the disc 40 from the turntable main body 22. In the embodiment, a magnetic material is used for the turntable body 22, and a magnetic adhesive 27 is used for the turntable body 22.
is used, the magnet 25 and the turntable main body 22 are magnetically connected, a magnetic closed circuit is formed between them and the yoke 48 of the disk 40, and the magnetic attraction force of the magnet 25 becomes effective. Demonstrated.

Although one embodiment of the present invention has been described above, the present invention is not limited to the embodiment, and various effective changes can be made based on the technical idea of the present invention.

For example, the elastic body referred to in the present invention is not limited to the disc spring shown in the embodiment, but various types of springs, rubber, etc.
It may also be made of plastic or the like.

The present invention is applicable to various disk turntables that magnetically chuck various types of disks, such as magnetic, optical, or magneto-optical.

[Effect of idea]

In this invention, the magnet is pushed into the recess against the elastic body up to a predetermined distance from the disk mounting surface of the turntable main body, and this magnet is adhered to the turntable main body, so that the disk mounting surface of the turntable main body can be easily attached. The distance accuracy between the surface and the magnet is not affected by the depth of the recess, the thickness of the magnet, dust, etc. between the recess and the magnet, and the distance accuracy can be ensured extremely accurately. Therefore, the chucking force by the magnet can always be kept at an optimum value, and the chucking force can be made uniform among a large number of turntables.

Moreover, according to the present invention, at least the disk mounting surface of the turntable body and the top surface of the magnet need to be formed with high precision, so the tolerances in the distance accuracy between the disk mounting surface and the bottom surface of the recess and the thickness accuracy of the magnet can be reduced. Can be expanded. Further, it is not necessary to completely remove dust and the like between the bottom surface of the recess and the magnet as in the conventional method. Further, the distance can be set extremely easily from the disk mounting surface side using, for example, a step jig. Therefore, processing and assembly of the turntable body, magnets, etc. can be performed extremely easily, and productivity during mass production can be greatly improved.

[Brief explanation of the drawing]

1 and 2 show an embodiment of a disc turntable to which the present invention is applied, and FIG. 1 is a vertical cross-sectional view of the main parts showing a state in which a magnet is bonded to the turntable body; FIG. 2 is a longitudinal sectional view showing a state in which the disk is chucked on the turntable main body. Further, FIG. 3 is a vertical cross-sectional view of a main part showing a state in which a disk is chucked on a turntable main body in a conventional example. In addition, in the symbols used in the drawings, 22...turntable body, 23...disc mounting surface, 24
... recess, 24a ... bottom surface of recess, 25 ... magnet, 25a ... upper surface of magnet, 26 ... elastic body, 27 ... adhesive, 30 ... step jig, 31 ...
... Reference surface, 32 ... Pressure surface, 40 ... Disk,
48...York.

Claims (1)

[Scope of Claim for Utility Model Registration] A turntable body having a disk mounting surface for receiving a disk, a chucking magnet installed in a recess provided in the turntable body, and a magnet installed between the magnet and the recess. an elastic body, the magnet is pushed into the recess against the elastic body up to a predetermined distance against the disk mounting surface, and the magnet is bonded to the turntable main body. Disc turntable.