JP2001319443A - Magnetic recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the shock resisting performance of a magnetic recorder by preventing a malfunction in the recording/reproduction of data caused by that a magnetic disk is deviated in the radial direction of the disk. SOLUTION: In order to hold the inner peripheral part of the magnetic disk 2 and the outer peripheral surface of a hub 11 so as to be in contact with each other, an opening groove 21 is formed at the hub and a wedge-shaped member 22 is provided in the center part of a hub apex. By fitting the member 22, the hub 11 is pressed and expanded in a radial direction and the outer peripheral surface of the hub is abutted on the inner peripheral part of the magnetic disk to surely fix the magnetic disk. Thus, the deviation of the magnetic disk can be reduced even in the case of the external shock, thereby, the shock resisting performance of the magnetic recorder can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording apparatus, and more particularly to a magnetic recording apparatus having a highly reliable spindle mechanism for fixing a magnetic disk against external impact.

[0002]

2. Description of the Related Art In a conventional magnetic recording apparatus, data is recorded or reproduced by a magnetic head on a magnetic disk rotated by a spindle mechanism. A head actuator rotatably provided around a pivot axis has a suspension arm having a magnetic head mounted at one end, and a coil fixed at the other end.

[0003] This coil constitutes a voice coil motor together with a magnetic circuit made of a yoke made of a permanent magnet and a magnetic material. The magnetic head is moved at high speed by the voice coil motor to position the magnetic head on the magnetic disk.

This spindle mechanism has a cylindrical hub and a clamp. The hub has a flange on the outer periphery and is held by bearings mounted on the shaft. The magnetic disk has a central opening inserted into the cylindrical hub and supported on a flange.

On the other hand, the clamp is fixed to the hub with bolts and the like, and the hub and the magnetic disk are integrally rotated by pressing the magnetic disk in the direction of the flange by the protrusion on the outer peripheral portion. .
This rotation is performed by a stator coil fixed to the base and a rotor magnet fixed to the hub.

[0006]

In recent years, magnetic recording apparatuses have been reduced in size and weight, and are required to be portable. Specifically, it is desired that the magnetic recording device is not broken even if it is accidentally dropped when being carried.

In a magnetic recording device, when a large horizontal impact is applied to the surface of a magnetic disk, the magnetic disk shifts in the radial direction of the disk. On the magnetic disk, a positioning signal is recorded in advance on a concentric circle with respect to the rotation center of the spindle.

For this reason, when a large shock is applied to the magnetic recording apparatus and the magnetic disk shifts in the radial direction, the rotation center of the spindle and the rotation center of the servo signal track written on the magnetic disk are shifted. In the worst case,
There has been a problem that the magnetic head cannot be positioned at a predetermined radial position, or the time required for positioning the magnetic head at a predetermined radial position becomes longer, thereby lowering the reliability or data access performance of the magnetic disk device.

In order to deal with this, as a first method,
Toshiba Open Technology Collection VOL. 14-25, pages 31 to 35, a method of inserting a plate material having a high friction coefficient into a portion where a magnetic disk and a flange and a magnetic disk and a clamp are in contact with each other to prevent displacement of the magnetic disk due to impact Has been proposed.

As a second method, a method of increasing the frictional force between the magnetic disk and the clamp, and between the magnetic disk and the flange by increasing the pressing force of the clamp that clamps the magnetic disk between the flange and the flange can be considered. ing.

However, when the clamping pressure is increased,
The pressing force from the clamp is applied to the flange, and the root of the flange is deformed. Since the flange and the magnetic disk are in close contact with each other, the magnetic disk is deformed following the deformation of the flange. As a result, there is a problem that the flying height of the magnetic head is increased and information from the magnetic disk cannot be recorded or reproduced.

The cause of the displacement of the magnetic disk is mainly due to a gap formed between the magnetic disk and the hub. Generally, the inner diameter of the central opening of the magnetic disk is slightly larger than the outer diameter of the hub in order to be inserted into the hub, so that there is a gap between the two after assembly.

For this reason, in the conventional magnetic recording device, there is an essential problem that the magnetic disk moves and shifts in the gap due to an external impact. Further, since the rotation center of the spindle and the rotation center of the magnetic disk cannot be matched, there is a problem that the spindle is eccentric when rotated. In the prior art, this point has been a problem when improving performance.

An object of the present invention is to provide a highly reliable magnetic recording apparatus which prevents the center of rotation of a spindle and the center of rotation of a magnetic disk from being displaced by an external impact in view of the above situation. It is in.

[0015]

The above-mentioned object is attained as follows. That is, in the magnetic disk of the present invention, a cylindrical hub is inserted into a central opening of the magnetic disk, and the magnetic disk is inserted between a flange provided on an outer peripheral portion of the hub and a clamp attached to the hub. The hub has an opening groove formed in a radial direction from a center portion to an outer peripheral portion.

Thus, for example, when a concave hole is formed in the center of the hub and a wedge-shaped member is inserted into the concave hole, the opening groove formed in the hub is pushed open in the groove width direction, and the outer peripheral surface of the hub is magnetic. The magnetic disk is fixed in contact with the inner peripheral edge of the disk.

A magnetic recording system comprising: a magnetic disk; positioning means for moving and positioning a magnetic head along a recording surface of the magnetic disk; and a spindle mechanism comprising a hub and a clamp for supporting the magnetic disk. The apparatus is characterized in that a hub having an opening groove extending radially from the center of rotation of the spindle to the outer peripheral portion, and a wedge-shaped member fitted to the hub and pushed in the groove width direction are provided.

According to this configuration, since the inner peripheral edge of the magnetic disk is fixed by the outer peripheral surface of the hub, stable performance can be maintained without impact of the magnetic disk, even if it is dropped. It is also advantageous in terms of cost.

Further, since the hub structure has at least two or more opening grooves, the inner diameter portion of the magnetic disk can be fixed at a plurality of locations, so that the hub can receive shocks from various directions. Secure fixing is possible.

Further, in the structure of the hub, the deformation of the flange is reduced by providing the opening groove and the groove along the circumferential direction of the outer peripheral surface of the hub, thereby preventing the deformation of the magnetic disk.

The hub has a structure in which the diameter of the hub is increased in the radial direction as described above, and a semi-ring type holding member for holding the inner peripheral edge of the magnetic disk, and a holding member on the outer peripheral surface of the hub. By providing the abutting projections, even if an impact is applied, the displacement of the magnetic disk can be prevented and the deformation of the magnetic disk can be prevented, so that the performance of the magnetic recording device can be improved.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the first embodiment.

As shown in FIG. 1, the magnetic recording apparatus according to the present embodiment includes a hub 11 for holding the magnetic disk 2, a clamp 13 for fixing the magnetic disk 2 to the hub 11, and a shaft 14 which is a rotating shaft of the hub 11. The motor includes a wedge-shaped member 22, a bearing 15, a stator 19 and a rotor 20 as a motor, and a head actuator on which a magnetic head and a suspension are arranged.

Now, the spindle mechanism 1 of the magnetic recording apparatus, which is an essential part of the present invention, will be described in detail. Also,
In the spindle mechanism, components other than the hub 11 will be described first, and the hub 11 will be described later.

The bearing 15 is mounted between the shaft 14 and the base 18. In the internal space of the hub 11, a stator 19 and a rotor 20 constituting a motor are provided.
Is incorporated. The stator 19 has a motor coil, is disposed to face the rotor 20, and is fixed to the base 18.

The rotor 20 is made of a permanent magnet, and is fixed to the inner wall surface of the hub 11. By passing a current through the coil, the hub 11a can be rotated on the bearing 15 together with the rotor 20.

Next, the configuration of the hub 11 will be described with reference to FIG. FIG. 2 is a perspective view when cut along the center of rotation of the hub and parallel to the opening groove 21 provided from the center of rotation of the spindle to the outer periphery. The hub 11 has the form of a hollow cylinder open at one end. The plate thickness was set to 1 mm in this example. The flange 12 is arranged around its open end and is formed integrally with the hub 11.

Further, the hub 11 in this embodiment is provided with an opening groove 21 having a width of 0.1 mm extending from the center to the outer periphery except for the flange 12 and the shaft 14. In FIG. 2, a thinly shaded portion is an opening groove 21. The opening groove 21 in the outer peripheral edge of the hub was opened to a position at the same height as the magnetic disk supporting surface of the flange 12.

As shown in FIGS. 1 and 2, the opening groove 21 is a crack formed on the top (upper surface) and a part of the peripheral wall of the cylindrical hub 11 which are not opened. The hub is formed to be elongated and linear in the radial direction up to the outer peripheral portion, and is elongated and opened to the portion corresponding to the groove bottom near the flange 12 of the shaft 14 and the hub peripheral wall to divide the hub upper surface portion and the side wall portion.

In this embodiment, the hub top divided by the opening groove 21 is cut into the shaft 14 at the center of the hub and integrated with the shaft 14. In the peripheral wall portion of the hub, the base of the flange 12 (FIG. 1) or the flange 12
2 is divided to an arbitrary position such as the same height as the magnetic disk support surface (FIG. 2), and the portion including the flange 12 is integrated.

The wedge-shaped member 2 is located at the center of the hub 11.
2 can be inserted so that the corresponding wedge-shaped recess 23
Is provided. The wedge-shaped member 22 has a conical shape, and has a hole through which the bolt 16 passes.

The first reason why the shape of the wedge-shaped member 22 is conical is that when the spindle rotates, the wedge-shaped member 22 is rotated.
Secondly, when the wedge-shaped member 22 is inserted, the opening angle (displacement amount) at which the hub 11 opens to the outer periphery can be freely set.

As described above, in the conventional magnetic recording apparatus, when the magnetic disk 2 is inserted into the hub 11, the gap between the inner diameter of the magnetic disk 2 and the outer diameter of the hub 11 is about 0.05 mm on average. . Further, considering the tolerance variation between the inner peripheral surface of the magnetic disk and the outer peripheral surface of the hub, ± 0.02
mm.

As a result, the height from the magnetic disk surface to the wedge-shaped member 22 when the wedge-shaped member 22 is fitted varies. However, if the wedge-shaped member 22 is formed in a conical shape, the opening angle (displacement amount) at which the hub 11 opens to the outer periphery is closely related to the shape of the wedge-shaped member 22, that is, the depth at which the wedge-shaped member 22 is fitted to the apex angle. Therefore, the degree of freedom of design increases.

Specifically, when the magnetic disk 2 having a large tolerance is used, the depth of the wedge-shaped member 22 to be inserted is reduced by increasing the apex angle of the wedge-shaped member 22 to be inserted. The variation of the size is small. As a result, a design that can reduce variations in height becomes possible. In this example,
The apex angle was 10 degrees. As the material, a metal such as stainless steel or the like, which is the same material as the hub, or a plastic member is preferable.

In such a configuration, the magnetic disk 2 is disposed on the flange 12, and the wedge-shaped member 22 is fitted into the wedge-shaped concave hole 23 at the center of the hub 11. As a result, the opening groove 21
Is expanded by the wedge-shaped member 22 in a direction perpendicular to the groove width, that is, the elongated opening, and a part of the outer peripheral surface of the hub 11 is
It is possible to contact the inner peripheral edge of the magnetic disk 2. The situation is shown in FIG.

Further, as shown in FIG.
Of the clamp 13 is fixed to the shaft 14 from above the clamp 13 by the bolt 16.

As described above, the opening groove 21 is formed in the hub 11.
By fitting the wedge-shaped member 22 to the hub, the elongated opening is uniformly pushed and widened in the outer circumferential direction where the groove width is opened, so that there is no substantial gap between the inner circumferential surface of the magnetic disk and the outer circumferential surface of the hub. Thus, even if a shock is input, the magnetic disk does not shift.

Further, since the center of rotation of the spindle and the center of the magnetic disk are maintained concentrically, it is possible to prevent the magnetic disk from being eccentric with respect to the rotation of the spindle.
Further, the present embodiment is advantageous in terms of cost because the conventional hub has a structure in which a dividing groove (opening groove 21) is provided at the top and only a wedge-shaped member is provided.

Next, a second embodiment and a third embodiment will be described with reference to FIGS. The difference between the first and second embodiments and the first embodiment is that at least three or more opening grooves radially extending from the center of the spindle to the outer periphery are provided.

As a result, the number of contact points between the outer peripheral surface of the hub and the inner peripheral edge of the magnetic disk increases, so that the magnetic disk can be held more reliably. Further, since the number of contact points between the inner peripheral edge of the magnetic disk and the outer peripheral surface of the hub increases, the contact area increases. As a result, the concentration of the stress supporting the magnetic disk can be reduced.

FIG. 4 shows a second embodiment in which three divided grooves (opening grooves 21a) are provided at the top of the hub 11, and the outer peripheral surface of the hub and the inner peripheral edge of the magnetic disk are brought into contact at three places. It is a top view which shows an apparatus. FIG. 5 is a top view of the apparatus according to the third embodiment in which four opening grooves 21b are provided at the top of the hub 11 and the outer peripheral surface of the hub and the inner peripheral edge of the magnetic disk are brought into contact at four points.

Since the basic structure of FIGS. 4 and 5 is the same except for the hub 11, the case where the hub 11 of the third embodiment is provided with four opening grooves will be described.
FIG. 6 is a cross-sectional perspective view of the third embodiment shown in FIG. 5, which is parallel to the opening groove 21b and cut at the rotation center of the spindle.

As shown in FIG. 6, the hub 11 is provided with an opening groove 21b having a width of 0.3 mm extending from the center to the outer periphery except for the flange 12 and the shaft 14. further,
In this configuration, another opening groove is provided from the center to the outer peripheral portion at right angles to the length direction of the opening groove 21b.

In FIG. 6, a thinly shaded portion is an opening groove. The opening groove 21b on the outer peripheral wall of the hub 11 was opened to a position at the same height as the magnetic disk support surface of the flange 12, as in the first embodiment. Further, the wedge-shaped concave hole 2 is inserted into the center of the spindle so that the wedge-shaped member 22 can be inserted.
3 are provided.

With this configuration, the magnetic disk 2 and the wedge-shaped member 2
2 and are incorporated. In addition, the protrusion 17 of the clamp is brought into contact with the magnetic disk 2, and is fixed to the shaft 14 from above the clamp 13 by the bolt 16.

By the way, it has been found that the following two points need to be taken into consideration in implementing the second and third embodiments. One is the hub falling rigidity,
Another is deformation of the flange portion.

First, the shaft falling rigidity will be described. Generally, high rigidity is desired. If the stiffness is low, the natural frequency decreases, and the response amplitude due to external vibration increases. As a result, the flying performance of the magnetic head is degraded, and the high performance of the magnetic recording device is hindered.

Table 1 shows the results of eigenvalue analysis performed on the shaft-tilting natural frequencies of the second and third embodiments when the rotation is stopped. In addition, the case of a conventional spindle mechanism in which an opening groove (divided groove) is not provided in the hub is also shown.

[0050]

[Table 1]

From Table 1, as the number of open grooves increases,
It was found that the spindle tilt frequency became smaller. This is because the rigidity of the contact point between the shaft 14 and the hub 11 decreases as the number of the opening grooves increases, and as a result, the natural frequency decreases.

Therefore, in the second and third embodiments, an optimum hub thickness is determined by a finite element within a range where there is no problem in mounting so as to achieve the same rigidity as when no opening groove is provided. We perform structural analysis by the method.

FIG. 7 shows a hub 11 having four open grooves.
2 shows the results of analysis on the relationship between the hub plate thickness and the shaft tilt frequency. In addition, the analysis results in the case where the opening groove is not provided in the hub 11 are also shown.

From FIG. 7, it can be seen that if the plate thickness of the hub is not less than 1.23 mm, the shaft tilt frequency is almost the same as that in the case where the hub has no opening groove. Hub thickness is 1.2
At 3 mm, it was confirmed that there was no problem in mounting, and this value was used in the third embodiment. Similarly, it goes without saying that there is no problem in the second embodiment.

Next, the deformation of the flange will be described. In the present invention, when the opening groove 21 is pushed outward in the outer peripheral direction by the wedge-shaped member 22 and the outer peripheral edge of the hub 11 contacts the inner peripheral edge of the magnetic disk 2, the flat portion of the flange 12 is inclined in the outer peripheral direction. Deform. This deforms the entire magnetic disk surface. This is shown in FIG.

It has been found that the cause is that a moment acts on the flange root A because the outer peripheral edge of the hub 11 spreads to the outer periphery. However, unlike the case of the conventional apparatus, unlike the case where a large pressing force from the clamp 13 is applied to the flange 12 and the magnetic disk 2 is deformed,
In the present embodiment, since the magnetic disk 2 is fixed at the inner peripheral edge, it can be clamped with a small force.

As a result, it was found that the deformation of the entire magnetic disk surface of the present invention was equivalent to the deformation of the magnetic disk generated by the conventional apparatus. Further, in order to reduce the deformation of the magnetic disk, the thickness of the flange root A may be increased as shown in FIG. In the present embodiment, the thickness of the root A of the flange is set to 1.5 mm.

With the above-described configuration, the magnetic disk 2 surely comes into contact with the outer peripheral edge of the hub 11 separated by the opening groove at several places, so that the magnetic disk 2 is subjected to impact from various directions. Deviation can be prevented.

Next, a fourth embodiment will be described with reference to FIG. The difference between this embodiment and the first embodiment is that
In the present embodiment, a groove 21c is provided along the outer peripheral surface of the hub 11 in order to reduce the deformation of the flange 12 without increasing the thickness of the flange base A.

FIG. 9 is a sectional perspective view of the hub unit of the fourth embodiment. A groove 21c having a depth in the radial direction of a cylindrical hub is provided near the flange 12 on the outer peripheral edge of the hub 11.
Are provided along the circumferential direction of the outer peripheral surface of the hub. In this example, the groove 21c has a depth of 0.4 mm and a width of 0.15 mm.
Set to.

As described above, by providing the groove 21c along the circumferential direction near the flange 12, the outer peripheral edge of the hub can be easily deformed in the outer peripheral direction around the groove 21c. Furthermore, since the moment of the hub 11 to the flange 12 can be reduced, deformation of the flange, that is, deformation of the magnetic disk can be prevented without increasing the thickness A at the base of the hub.

Next, a fifth embodiment will be described with reference to FIG.
This will be described with reference to FIG. The difference between this embodiment and the first embodiment is that a hub 11 having an opening groove 21e similar to that of the first embodiment is used for the purpose of reducing the deformation of the magnetic disk.
And a semi-ring type holding member 24 for holding the inner peripheral edge of the magnetic disk 2 while forming a projection 26 on the outer peripheral surface of the magnetic disk 2.

FIG. 10 is an assembly view, and FIG. 11 is a sectional view of the structure. The hub 11 is provided with two opening grooves 21e radially extending to the outer circumference through the rotation center of the spindle, and is provided with a semicircular arc-shaped projection 26. Opening groove 2 at this time
The same effect can be obtained if the number of 1e is two or more.

In addition, the flange arranged around the open end of the cylindrical hub 11 is eliminated, and the structure has only the flange base A. In this example, the thickness of the flange base is 2.
5 mm. The semi-circular arc-shaped protrusion 26 is
It is preferable that it is formed integrally with 1.

The half-ring type holding member 24 is formed with a U-shaped groove 25 so that the magnetic disk 2 can be inserted into the outer peripheral edge of the hub. As the material of the half-ring type holding member 24, metal such as ceramics of the same quality as the magnetic disk 2 or stainless steel of the same quality as the hub 11 is preferable, but plastic may be used.

The inner peripheral edge of the magnetic disk 2 was inserted into the U-shaped groove portion 25 of the half-ring type holding member 24, and further inserted into the hub 11 so that the holding member outer surface 24 b came on the flange base A. . Then, the wedge-shaped member 22 was fitted into the wedge-shaped concave hole 23 at the center of rotation of the spindle, and the clamp 13 was fastened with the bolt 16.

The place where the clamp projecting portion 17 presses is the semi-ring-shaped holding member outer surface 24a. With this configuration, the magnetic disk 2 and the half-ring type holding member 24 are in close contact with each other, and the contact area of the contact portion is increased, so that the magnetic disk is fixed by the pressing of the arc-shaped projection 26 on the outer periphery of the hub. You. Further, since the thickness of the flange base A on which the magnetic disk is arranged is configured to be thick,
The deformation of the magnetic disk is suppressed.

In this embodiment, the holding member 24 is formed as a half-ring type divided into two parts to reduce the number of parts.
It may be a divided or more arcuate holding member. Also, the protrusion 26 on the outer peripheral surface of the hub may not be arc-shaped,
It does not have to be continuous in the circumferential direction.

With this configuration, the inner peripheral end face of the magnetic disk can be pressed uniformly, and the magnetic disk can be reliably held against external force due to impact. Therefore, it is possible to provide a highly reliable magnetic recording device that is resistant to impact.

[0070]

As described above, according to the present invention, it is possible to prevent the magnetic recording apparatus from being displaced in the radial direction with respect to the hub when the magnetic recording apparatus receives an external impact regardless of whether it is operating or not operating. It becomes possible. Therefore, a data reading error due to an impact is eliminated, and a highly reliable magnetic recording apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a spindle mechanism according to a first embodiment.

FIG. 2 is a sectional perspective view of the hub according to the first embodiment;

FIG. 3 is a top view of the hub and the magnetic disk of the first embodiment.

FIG. 4 is a top view of a hub and a magnetic disk provided with three opening grooves according to a second embodiment.

FIG. 5 is a top view of a magnetic disk and a hub provided with four opening grooves according to a third embodiment.

FIG. 6 is a sectional perspective view of a hub in which four opening grooves are provided in the third embodiment.

FIG. 7 is a diagram showing an analysis result on a relationship between a hub plate thickness and a shaft falling frequency.

FIG. 8 is a modified view of a flange base.

FIG. 9 is a sectional perspective view of a hub according to a fourth embodiment.

FIG. 10 is an assembly diagram of a hub, a magnetic disk, and a clamp according to a fifth embodiment.

FIG. 11 is a sectional view of a hub according to a fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spindle mechanism 2 Magnetic disk 11 Hub 12 Flange 13 Clamp 14 Shaft 15 Bearing 16 Bolt 17 Clamp protrusion 18 Base 19 Stator 20 Rotor 21, 21a, 21b, 21d, 21e Opening groove 21c Groove part 22 Wedge-shaped member 23 Wedge-shaped concave hole 24 Half Ring-type holding members 24a, 24b Half-ring-type holding member surface 25 U-shaped groove-shaped portion 26 Semi-arc-shaped protrusion A A flange base

Claims (6)

[Claims] A cylindrical hub is inserted into a central opening of a magnetic disk, and the magnetic disk is sandwiched between a flange provided on an outer peripheral portion of the hub and a clamp attached to the hub. A magnetic recording apparatus, wherein the hub has an opening groove formed in a radial direction from a center portion to an outer peripheral portion. 2. The hub has a concave hole in the central portion,
2. The magnetic recording apparatus according to claim 1, further comprising a wedge-shaped member inserted into the concave hole. 3. A cylindrical hub having a magnetic disk for recording information and positioning means for moving and positioning a magnetic head along a recording surface of the magnetic disk, and having a flange for supporting the magnetic disk. A spindle mechanism that is attached to the hub and that clamps the magnetic disk to the flange, the hub having an opening groove that extends linearly from a central portion to an outer peripheral portion, A concave hole formed in the center,
A wedge-shaped member inserted into the concave hole to push the hub radially. 4. The hub has at least two or more opening grooves, and is configured such that an outer peripheral surface of the hub comes into contact with an inner peripheral edge of the magnetic disk by being pushed open in a radial direction. 4. The magnetic recording device according to claim 1, wherein the magnetic recording device comprises: 5. The hub according to claim 1, further comprising:
5. The magnetic recording apparatus according to claim 1, wherein a groove having a depth in a radial direction is formed. 6. An inner peripheral edge of the magnetic disk is held by at least two or more divided arc-shaped holding members, and a projection that can contact the arc-shaped holding member is provided on an outer peripheral surface of the hub. The magnetic recording device according to any one of claims 1 to 5, comprising: