JPS6124050A - Chucking device of magnetic disc recording and reproducing device - Google Patents

Abstract

PURPOSE:To realize sure chucking by applying a cover to reduce friction to a part where a recording medium is brought into contact with a drive shaft. CONSTITUTION:An attracting ring 16 made of a ring permanent magnet is provided to a chuck reference member 15 formed to a bowl and an annular upper end face 17 is a chuck support face. A TiN thin layer 28 as a substance corresponding to any of carbide, nitride or carbon nitride of groups III, IVa, Va or VIa of the periodic table is coated on the face 17. It is preferred to form the thin layer 28 by the physical vapor deposition method (pVD method) or the chemical vapor deposition method (CVD method). The friction coefficient is improved remarkably by the thin film layer 28 formed in this way, the restriction in a disc plane is not hindered and rotating eccentricity is prevented.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a chucking device for a magnetic disk recording and reproducing device, and more particularly to an improvement of a magnetic chucking mechanism for a magnetic disk recording and reproducing device.

(Prior Art) In recent years, magnetic disk recording and reproducing devices have come to be widely used for recording computer information. This is because magnetic disk devices have random access properties and are capable of high-density recording, making them suitable for this purpose.

In this magnetic disk recording and reproducing device, in order to improve the so-called recording density by reducing the track pitch and increasing the track density, eccentricity between the rotation center of the magnetic disk and the rotation center of the drive shaft on the recording/reproducing device side is minimized. There is a need for this, and various proposals have been made for this purpose.

In conventional disk drives, a magnetic disk is usually mounted on a spindle shaft, and a rotating pressing member presses the magnetic disk onto the spindle shaft, thereby transmitting rotation using the frictional force.

This method has the disadvantage that the load torque on the rotating spindle shaft increases due to thrust force and the like. For this reason, magnetic chucking using permanent magnets has been proposed to simplify the chucking mechanism [the mechanism that attaches the magnetic disk to the drive shaft (spindle) of the recording/reproducing device] and to reduce the rotational load on the spindle shaft. ing.

Figures 1 and 2 (A), (B), and (C) show a magnetic disk jacket that uses magnetic chucking to minimize eccentricity and the drive mode of the recording/reproducing device that drives the disk. and shows the spindle axis.

A magnetic disk jacket 1 has openings 2 provided on the front and back sides for a magnetic head to contact and scan for recording and reproduction.
and a positioning hole 4 for positioning the jacket 1 toward the recording/playback device when it is attached to the recording/playback device. .4 is provided. A magnetic disk 5 is loosely and rotatably inserted into the jacket 1, and a center positioning member 6 made of synthetic resin is provided at the center of the magnetic disk 5. This center positioning member 6 is provided with a fitting hole in the shape of a pentagonal home base that engages with the spindle 9 on the side of the recording/reproducing device. A leaf spring 7 is inserted vertically to fit the spindle 9 without eccentricity. Therefore, this leaf spring 7 and the inner wall 8. .

8, the disk 5 can be mounted on the spindle 9 without eccentricity of its rotation center. As shown in FIGS. 2(A) and 2(B), the center of the jacket 1 is provided with a through hole 10 on the front and back sides, and the magnetic disk 5 is inserted through a donut-shaped suction yoke 11 made of an iron plate. The positioning member 6 is attached to a stepped portion in the middle of the outer circumference and inserted into the jacket.

A plastic annular member 12 is attached to the lower surface of the suction yoke 11, and is configured to prevent dust from entering the jacket 1 and to provide positioning.

Now, when the positioning holes 4, 4 of the magnetic disk jacket 1 are fitted to the positioning pins (not shown) of the recording/reproducing apparatus and the recording/reproducing apparatus is installed, the motor 1 of the recording/reproducing apparatus shown in FIG.
A positioning member 6 for the magnetic disk 5 in the jacket 1 is fitted into the spindle 9 provided on the shaft 14 of No. 5.

The spindle 9 consists of a short cylindrical spindle shaft and a chuck reference member 15 formed around it in the shape of a bowl,
This is integrally attached to the seventh shaft 14 of the motor 13, and a permanent magnet attraction ring 16 formed in an annular shape is arranged in the seventh bowl-shaped groove.
The upper end of the chuck receiver is a surface 17. The positioning member 6 of the magnetic disk 1 is connected to its leaf spring 7 and inner wall 81w8.
At the same time, the attraction ring 16 attracts the attraction yoke 11 of the magnetic disk 1, causing the yoke 11 to come into contact with the surface 17 of the magnetic disk 1, thereby preventing chucking. is configured to be performed.

However, in the magnetic chucking configured in this way, as can be easily understood from the diagram, the attraction force generated between the attraction ring 16 and the attraction yoke 11 is a force in a direction perpendicular to the disk surface. Yes, - 10,000 The acting force by the spring 7 for centering is the inner wall a + tat
This is the in-plane force that presses the magnetic disk against the magnetic disk. That is, basically, only slight effects such as dimensional difference in spindle diameter (4 μm or less) and rotational runout of the spindle (2 μm or less) occur, so no clearance occurs.

The relationship between these two forces, that is, the centering force of the spring and the attraction force of the magnet, involves important issues regarding centering and reliable chucking. That is,
If the value obtained by multiplying the spring force by the coefficient of friction between the spindle 9, the inner walls 8t and 82, and the spring 7, that is, the insertion resistance generated by the spring force is greater than the adsorption force, then the insertion resistance caused by the magnet itself (due to the adsorption force) ) The sword does not perform adsorption action, that is, chucking. The magnetic disk ends up being held in a state where it is tilted with respect to the spindle and does not come into contact with the chuck receiver.

-At this time, another problem occurs due to the following mechanism. That is, for example, the inner walls 8□, 8. .

If the surface of the spring 7 is not exactly perpendicular to the suction yoke 11 (for molded products such as plastic, this can easily change depending on the temperature conditions during molding, etc.). If the frictional force generated by some vector components of is large, centering by the spring is ineffective, that is,
Inner wall 8□ or inner wall 87. Or inner wall 8. and inner walls8. A gap will be generated between the spindle 9 and the spindle 9, and centering will not be performed satisfactorily.

Conventionally, the solution to this problem was to use the former condition, that is, to set the suction force relatively weak, to set the centering spring force strong, and to press once from the outside where the suction was insufficient. A mechanism was set up. However, this device is complicated and relatively expensive.

(Purpose) The present invention has been made in view of the above circumstances, and although the relationship between the spring force for centering and the attraction force of the magnet remains the same as before, it eliminates the need for external pressing means, and We provide a chucking device for magnetic disk recording and reproducing devices that can achieve reliable chucking. Specifically, the magnetic chucking device has a coating or a protruding member that reduces friction on the part that comes into contact with the magnetic disk. By providing this, chucking can be performed reliably.

(Summary) To achieve the above object, the present invention uses carbides, nitrides, or carbonitrides belonging to Group Ⅰ, IVa, Va, or Ⅰa of the periodic table to reduce friction. A surface treatment method in which a thin layer of material is coated on the mounting part that contacts the magnetic recording medium, or the chuck receiver has an arcuate protruding surface instead of the conventional flat shape to reduce the load when the magnetic disk slides sideways. This method employs a mechanical contact friction reduction method.

In the surface treatment method, it has been confirmed that the thin layer of the above material has excellent hardness and the frictional resistance value is less than half, and is a reactive method with strong covering power even among physical vapor deposition methods (PVD methods). An excellent magnetic disk chucking device was obtained by coating the abutting portion using the ion blating method. .

However, in the mechanical contact friction reduction method, it is very easy to control the abutting part to have a protruding shape or a metal ball, for example, in the plane of the support part, and the above-mentioned conventional drawbacks can be suppressed.

(Example) Hereinafter, the present invention will be described in detail based on the drawings. FIG. 3 shows a partially enlarged sectional view of the spindle portion showing the structure of the present invention. Chuck reference member 1 shaped like a bowl
5 is provided with an adsorption ring 16 made of an annular permanent magnet, and an annular upper end surface 17 serves as a chuck receiving surface.

This surface 17 is coated with a TiN thin layer 2B, which is a material corresponding to any one of carbides, nitrides, and carbonitrides of elements of group 1, group IVa, group va, or group 2a of the periodic table.

This thin layer 28 is formed using a physical vapor deposition method (PVD method) or a chemical vapor deposition method (CVD method).
-It is better to be familiar.

According to experiments conducted by the present inventor, it has been confirmed that the Vickers hardness of a thin TiN layer formed by applying the PvD method on the surface of stainless steel such as 8Uf9+03 is approximately HV=2000 or higher. . It has also been confirmed that the frictional resistance value is less than half of the conventional value.

The present inventor used a reactive ion blating device, which has a particularly strong covering power among PVD methods, for coating TiN.

This device is shown in FIG. The sample 52 in the bell jar 51 is configured such that a sample mount 53 mounted in a skewer shape rotates in the direction of an arrow 53a and revolves in the direction of an arrow 53b by the driving force of a motor 54. A negative voltage is applied to the sample mount 53 by a base voltage power source 55, and the sample 52 is thereby negatively charged. In the figure, reference numeral 56 denotes an evaporation source containing Ti, and Φi is evaporated by applying a beam from a beam dragon 57 as shown by the arrow. Further, an ionization electrode 59 is provided above the evaporation source 56F), and this electrode 69 connects the evaporation source 56 and the ionization electrode 59.
The space between the two becomes a plasma state, and the evaporated Ti is ionized. The ionized titanium is accelerated toward the sample mount 53 and collides with the sample 52 with kinetic energy to form a Ti layer. Also, gas system 60
When N gas is introduced from the sample 52, the N gas becomes a plasma, accelerates toward the sample mount 56, and forms a TiN layer on the sample 52. Note that after forming the Ti layer, T
The conditions for forming the iN layer were an ionization power source of 40V.

The base voltage is 100v.

The thin film layer 28 formed in this way significantly improves the coefficient of friction, does not interfere with the regulation within the disk plane, and can prevent rotational eccentricity.

Next, FIG. 5 is an enlarged sectional view of a spindle portion showing an embodiment of the present invention using a mechanical contact friction reduction method.

The spindle 9 attached to the shaft 14 of the drive motor 16 has a short four-cylindrical spindle shaft and a bowl-shaped chuck reference member 15 integrally formed. A t+jyi ring 16 made of a permanent magnet is attached. In this embodiment, the portion 18 of the Teha spindle 9 that comes into contact with the center core is formed into a spherical shape (a part of a spherical surface or a rotated cylindrical shape).

With this configuration, the magnetic disk positioning member 6
Even if the inner wall 8ts82 and the spring surface of the spring 7 are not exactly perpendicular to the suction yoke 11, there will be no obstruction that would obstruct suction. Of course, this eliminates the need for an abutment part for the perpendicularity of the spindle 9 and for accurate perpendicularity (parallelism to the axis of rotation), thereby increasing productivity. In this embodiment, the abutting portion is made spherical to reduce friction, but the same effect can be obtained by making the length of the abutting portion sufficiently small.

Next, a second embodiment will be described based on FIG.

FIG. 6 is a partially enlarged cross-sectional view of the chuck receiving surface 17, in which the chuck receiving surface 17 rotates in a round shape and is formed into a round shape.

As a result, when placing the magnetic disk 5, the chuck receiving surface 1
7 is in line contact with the suction yoke 11, the load of the suction yoke 11 from sliding sideways is reduced, the suction yoke 11 becomes easier to slide, and reliable chucking can be performed.

FIG. 7 is a perspective view of the chuck reference member 15, showing a further improvement of the embodiment shown in FIG. 6 above. In the case shown in FIG. 6 above, the entire circumference of the chuck receiving surface 17 is shaped like a sphere in vertical cross section, but in this embodiment, only three equally spaced portions on the chuck receiving surface 17 are formed. A convex portion 19 is formed on the top surface, and the upper surface thereof is eight.

This further reduces contact friction.

FIG. 8 shows an enlarged perspective view of a part of the chuck receiving surface 17. In this embodiment, the three convex portions 1 shown in FIG.
9 has a curved surface in the circumferential and longitudinal direction as shown in the figure, and the contact area is smaller than that of the embodiment shown in Fig. 7, so that the friction can be further reduced. Reliable chucking can be achieved with both adsorption and suction.

9a and 9b are partially enlarged cross-sectional views of the chuck reference member 15 showing still other embodiments. The protrusions are made by attaching balls or brass balls at three equal intervals. In the embodiment shown in FIG. 9a, a ball guide 22 having a locking claw 211 is bonded to the upper end surface of the chuck reference member 15 in a concave valve 22a made of synthetic resin into which a ball enters, and a steel ball or Brass ball 20
It is determined by the arrangement of .

23't- is provided, and the above-mentioned ball 20 is fixed with an adhesive 24. The examples shown in Figures 6 to 8 above have poor workability and reduce productivity, but this example improves the process, reduces the friction coefficient, and ensures both centering and suction. .

In the one shown in FIG. 10, the hole portion of the concave valve 22a of the ball guide 22 shown in FIG. 9a is enlarged to form four parts 23 in which the ball 20 can freely rotate. Thus, ball 2
Since 0 is held with a certain degree of freedom, the coefficient of friction can be lowered even further than that shown in FIG. 9a.

Furthermore, in the embodiment shown in FIG. 11, a permanent magnet 25 is provided at the bottom of the center of the recess 23 of the hole into which the ball 20 of the ball guide 22 of the chuck reference member 15 of the chuck reference member 15 of FIG. 10 is inserted. When taking out the ball 20, the ball 20 is subjected to a weak sword action which brings it approximately to the center of the recess 25, thereby making the effect more reliable.

In the embodiment shown in FIG. 12, the permanent magnet 2 shown in FIG.
Instead of the magnetic force located at the center of 5, a weak spring 26 is placed at the center of 3.
I used a book. This force acting on the center needs to be weak so as not to interfere with centering.

FIG. 13 shows yet another embodiment. In this example, unlike the embodiment shown in FIGS. 9 to 12, the ball guide 22 is not used, but three recesses 27 are provided at equal intervals on the circumferential surface of the upper end surface of the chuck reference member 15. , a metal ball 20 is inserted into this recess 27. In this example, by applying grease or the like to the metal ball 20 and the four parts 27 in the recess 27, the metal ball 20 can rotate with low friction inside the recess 27, thereby reducing the coefficient of friction. In this example, the metal balls 20 are provided at three locations in the circumferential direction on the upper end surface of the chuck reference member 15, but they may be provided at several locations as necessary.

In this way, by inserting the metal ball, the contact between the magnetic disk surface and the east spindle on the device side is a point contact with one ball, and the metal ball itself rotates easily due to grease etc., so the disk Friction within a plane is extremely small. Therefore, in-plane regulation is very easy to perform, and the drawbacks of the conventional method can be overcome.

(Effects of the Invention) As described above, the present invention provides that the contact portion between the magnetic disk and the magnetic chucking device such as the spindle of the recording/reproducing device that drives the magnetic disk is coated with a thin film such as TiN to reduce friction. Since it is formed by a contact member close to a point contact of a nest-like member or a metal ball, the coefficient of friction can be reduced, and the contact between the magnetic disk and spindle can be made smoothly without eccentricity, making it more reliable than a chucking metal. It can be made into something.

[Brief explanation of drawings]

Figure 1 is a plan view showing a conventional magnetic disk jacket that uses magnetic chucking, and Figure 2 (A) (
B) (C) is an enlarged plan view and cross-sectional view of the main parts of the magnetic disk jacket shown in FIG. FIG. 3 is an enlarged cross-sectional view of the main part of a chuck reference member showing an embodiment coated with a thin film according to the present invention, and FIG. 4 is a reactive ion block diagram used in the embodiment of FIG. 3 above. 5 is an enlarged sectional view of a spindle portion showing one embodiment of the present invention; FIG. 6 is a part of a chuck reference surface showing another embodiment of the present invention; FIG. FIG. 7 is an enlarged perspective view of a chuck reference member showing still another embodiment of the present invention; FIG. 8 is a partially enlarged view of the chuck reference member showing a modification of the embodiment shown in FIG. 9a, 9b, 10 and 11 are enlarged cross-sectional views of parts of the chuck reference member showing other embodiments of the present invention, and FIG. FIG. 13 is an enlarged plan view of a part of the chuck reference member showing still another embodiment of the invention.
FIG. 7 is an enlarged cross-sectional view of a portion of a chuck reference member showing still another embodiment of the present invention. 1...Magnetic disk jacket 5...Magnetic disk 6...Magnetic disk positioning member 7...
Leaf springs s, t e,...Inner wall 9, φ...Spindle 11...Adsorption yoke 15...Chuck reference member 16...Permanent magnet 17...Chuck The receiver is a surface 18... Protruding portion 19... Convex portion 20... Sphere 28... TiN thin layer patent applicant Olympus Optical Industry Co., Ltd. 1
Diagram T-) 2 Ward 4 Tsuta 8 Drawing Horse 9o Drawing Chi 9b Ward Suji 10 drawing

Claims (2)

[Claims] (1) In a magnetic chucking device for a magnetic recording and reproducing device that has a motor that drives a disc-shaped recording medium that is removably attached thereto, the recording medium can be chucked without being eccentric to the drive shaft on the drive motor side. Therefore, a chucking device for a magnetic disk recording/reproducing device is characterized in that a coating is applied to the portion where the two contact each other to reduce friction. (2) In a magnetic chucking device for a magnetic recording and reproducing device that has a motor that drives a disc-shaped recording medium that is detachably attached thereto, the recording medium can be chucked without being eccentric to the drive shaft on the drive motor side. Therefore, a protrusion is provided on a member that is fixed to the drive motor and comes into contact with the disc-shaped recording medium,
A chucking device for a magnetic disk recording/reproducing device characterized by reduced friction.