JP2000315368A - Actuator locking mechanism for magnetic disk device or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator locking mechanism for a magnetic disk device, capable of preventing the magnetic force of a locking magnet from being applied as an external disturbance on the servo system of an actuator during the operation of the actuator, eliminating a reduction in a recording area on a magnetic disk, and suppressing variance in locking torque while an actuator is in operation. SOLUTION: In a magnetic disk device for locking an actuator 1 by attracting a locking pin 2a made of a magnetic member by a locking magnet 8 during the non-operation of the actuator 1, a sectional shape substantially vertical in the protruding direction of the locking pin 2a is polygonal in a portion intersecting the magnetic flux of the locking magnetic 8, and when the locking magnetic 8 attracts the locking pin 2, one vertex of the polygon is brought into contact with or approaches the locking magnet 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for restraining and locking the movement of a magnetic head or the like at a predetermined position in a magnetic disk drive or the like, and more particularly to a concrete means for locking an actuator of a magnetic disk drive or the like. It is characterized by the following.

[0002]

2. Description of the Related Art In a conventional magnetic disk drive, when starting or stopping, a data recording area on a disk surface as a recording medium is prevented from being damaged by a magnetic head. An area is provided.
When the power is off, the magnetic head is on the non-recording area. When the power is turned on and the rotation speed of the disk increases, the magnetic head flies above the disk surface. Thereafter, the motor rotates the actuator, moves the magnetic head at the tip of the actuator toward the outer periphery of the disk, and stops the magnetic head at a predetermined position on the recording area.

Here, when the power is turned off, the magnetic head on the non-recording area is moved to the recording area by an unexpected external force such as vibration, so that the magnetic head is located on the non-recording area so as not to damage the magnetic head. It is necessary to lock the actuator.

A conventional locking mechanism of a magnetic attraction type actuator using a locking magnet is disclosed in, for example,
-203516. Hereinafter, FIG.
A lock mechanism of the magnetic attraction type actuator according to the related art will be described with reference to FIG. 11 and FIG.

FIG. 10 is a perspective view of a lock mechanism of an actuator of a magnetic disk drive according to a conventional embodiment. FIG. 11 includes a lock magnet 8 and a lock pin 2 which are main parts of the lock mechanism of the actuator of the magnetic disk drive. It is an expansion perspective view of a part.

In FIG. 10, an actuator 1 is mounted so as to be rotatable about a rotation shaft 3 as a center of rotation. The actuator 1 is a voice coil motor (V
(CM) 4 as a drive source. A lock pin 2 made of a magnetic material is disposed at one end of the actuator 1. The magnetic disk 5 has a non-recording area on the inner circumference. Normally, when the actuator 1 is not operated, the magnetic head 6
Are retracted into this area, and move to the recording area via the suspension 7 attached to the actuator 1 when the actuator 1 operates.

As shown in FIG. 11, a cross section perpendicular to the projecting direction of the lock pin 2 (hereinafter, simply referred to as a cross section) has a square shape. The locking magnet 8 includes a magnetic head 6
Are located and fixed so that the mutually facing surfaces of the locking magnet 8 and the lock pin 2 are parallel to each other at the position of the actuator 1 where it exists on the non-recording area.

With the above configuration, when the actuator 1 is not operated, the lock pin 2 is attracted by the magnetic force of the locking magnet 8 and the actuator 1 can be locked.

[0009]

In the lock mechanism of the magnetic attraction type actuator as in the prior art, the lock torque (the lock pin 8 is attracted to the lock pin 2) with respect to the rotation angle of the actuator 1, which is ideal. A change in the torque that the force exerts on the actuator 1
It is called lock torque characteristic. ) Is indicated by the dashed line in FIG.

The characteristics of this ideal lock torque characteristic are as follows.
The lock torque value near the peak is sufficiently large and not excessive, and the lock torque attenuates sufficiently rapidly from the peak value with the increase of the rotation angle, and the lock torque corresponding to the recording area on the surface of the magnetic disk 5 is increased. That is, it is sufficiently small in the range of the moving angle. First, if the lock torque value near the peak is sufficiently large, the magnetic head 6 can be sufficiently locked on the non-recording area against an unexpected external force when the actuator 1 is not operating. Next, as the rotation angle increases, the lock torque attenuates sufficiently rapidly from the peak value, and if the lock torque is sufficiently small even in the range of the rotation angle corresponding to the recording area, the magnetic head 6 is moved to a predetermined position on the recording area. When moving to
The control of the actuator 1 by the servo system is facilitated because it is not affected by the lock torque. In order to easily realize the rapid decay of the lock torque, it is also important that the peak value of the lock torque is not excessive.

However, the lock torque characteristic actually shown by the conventional lock mechanism of the actuator is shown in FIG.
Or the solid line in FIG. 3 which emphasizes the difference between the curve and the ideal lock torque characteristic, and has the following problems.

The first problem is that the actuator 1
When the lock pin 2 is attracted and locked by the magnetic force generated by the lock magnet 8 during its non-operation, the value near the peak of the lock torque is excessively larger than the value required for locking. For this reason, even when the actuator 1 is operated, that is, when the rotation angle of the actuator 1 is in a range corresponding to a recording area on the surface of the magnetic disk 5, the magnetic force of the locking magnet 8 having a small but not negligible size. Sucks the lock pin 2 and acts on the servo system of the actuator 1 as a disturbance. The disturbance increases as the lock pin 2 approaches the lock magnet 8 and decreases as the lock pin 2 moves away, as indicated by the broken line in FIG. As described above, since the magnitude of the disturbance changes depending on the position of the lock pin 2, it is difficult to control the actuator 1. In particular, in a portion where control is difficult, it is impossible to avoid the influence of the magnetic head 6 on recording and the like, so that there is a problem that the recording area on the surface of the magnetic disk 5 must be reduced.

Next, a problem arises in that the deviation from the designed position of the lock pin 2 due to an error in assembling varies from product to product. Due to the deviation, the distance of the lock pin 2 from the locking magnet 8 when the actuator 1 is not operating varies from the design. The correspondence between the distance and the rotation angle of the actuator 1 also varies from a predetermined one. For this reason, the actual lock torque characteristics vary from the lock torque characteristics assumed in advance in control (hereinafter, referred to as lock torque variations). In the conventional example, there is a problem that the variation in the lock torque is large and it is difficult to control the actuator 1.

In order to reduce the peak value of the excessive lock torque to a necessary and sufficient value, it is conceivable that the locking magnet 8 has a weak magnetic force or the volume of the entire lock pin 2 is reduced. However, replacing the material of the locking magnet 8 with a conventional material is costly and impractical. Further, reducing the volume of the lock pin 2 has a limit in demanding a reduction in the size of the entire magnetic disk device. In addition, a deviation from the designed position of the lock pin 2 is likely to occur, and the deviation of the deviation is increased, so that the deviation of the lock torque is increased.

[0015]

In order to solve the above-mentioned problems, a lock mechanism for an actuator according to the present invention has a head means for recording or reproducing data on or from a recording medium, and supports the head means and has a predetermined structure. A carriage means rotatably provided about a rotation axis; a carriage driving magnet, a coil, and a yoke; and the head means is moved to a predetermined position on the recording medium by rotating the carriage means. An actuator provided on the carriage means, the actuator having a lock pin made of a magnetic member protruding in a direction substantially parallel to the rotation axis, and rotating about the rotation axis during operation; A lock provided to lock the rotation of the actuator by sucking the lock pin when the actuator is not operated. In a magnetic disk device having a Gunetto constitute a cross-sectional shape of the lock pin at a portion intersecting the magnetic flux of said locking magnet polygonal,
When the locking magnet attracts the lock pin when the actuator is not operated to lock the rotation of the actuator, one vertex of the polygon is brought into contact with or close to the locking magnet.

With the above arrangement, the attractive force exerted on the lock pin by the lock magnet is not excessive when the actuator is not operated, so that the lock torque characteristic of the actuator approaches the ideal shape described above. That is, during the operation of the actuator, the range of the rotation angle that is not so large that disturbance due to the lock torque makes the control of the actuator difficult is increased.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a lock mechanism for an actuator according to the present invention will be described below with reference to FIGS. Components having the same functions as those of the above-described conventional example are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 is a perspective view showing a lock mechanism of an actuator of a magnetic disk drive according to an embodiment of the present invention. FIG. 2 is an enlarged view of a lock magnet 8 and a lock pin 2a of the magnetic disk drive. 4 to 8 show the lock pin 2a and the lock magnet 8 in the lock mechanism of the actuator of the magnetic disk drive.
The inclination angle α (FIG. 2) between the angles 15 °, 30 °, 45 °,
It is a figure which shows the lock torque characteristic at the time of 60 degrees and 75 degrees. The curves shown in FIGS. 4 to 8 are optimal as curves representing lock torque characteristics from data of lock torque values actually measured at predetermined rotation angles (indicated by circles and triangles in each figure). It seems to be. FIG. 9 shows the lock torque characteristic of the conventional example in which the above-mentioned inclination angle α is 0 ° by a solid line, and the lock torque characteristic of the embodiment of the present invention in which the inclination angle α is 45 ° by a broken line.

In FIG. 1, the lock mechanism of the actuator of the present embodiment is different from that of the prior art in that the cross-sectional shape of the lock pin 2a is, for example, a square, and the apex angle in contact with or close to the locking magnet 8 is substantially. In that it is configured so as to be at right angles. That is, as shown in FIG.
When one corner of the cross section of the lock pin 2a contacts or approaches the lock magnet 8 at the lock position when the actuator 1 is not operated, one side surface of the lock pin 2a and the side surface of the lock magnet 8 oppose each other. They are arranged so as to form an inclination angle (hereinafter, this inclination angle is simply called an inclination angle).

According to the above configuration, the actuator 1 can be locked in the same manner as the above-described conventional actuator locking mechanism. That is, when the power is turned off,
The actuator 1 rotates toward the inner periphery of the magnetic disk 5 by using the electromotive force generated by the remaining rotation of the rotation motor of the magnetic disk 5 (not shown) for driving the voice coil motor 4. As the actuator 1 rotates, the magnetic head 6 moves to a non-recording area on the inner periphery of the magnetic disk 5. When the magnetic head 6 moves over the non-recording area, the lock pin 2a disposed at one end of the actuator 1 is attracted by the magnetic force of the locking magnet 8, and the actuator 1 is locked.

When the power is turned on, the voice coil motor 4 is started, and the actuator 1 rotates toward the outer periphery of the magnetic disk 5 by the driving force of the voice coil motor 4. As a result, the distance between the lock pin 2a and the lock magnet 8 is opened, and the lock of the actuator 1 is released.

Further, in the actuator lock mechanism according to the embodiment of the present invention, unlike the conventional lock mechanism, the inclination angle α (FIG. 2) is set to a constant value different from 0 °. Only by this setting, it was found by actual measurement that the lock torque characteristic of the embodiment of the present invention was closer to the ideal lock torque characteristic shown in FIG. 3 than that of the conventional example. Hereinafter, this will be described with reference to FIG.

As shown in FIG. 9, the lock torque characteristic (hereinafter referred to as α) when the inclination angle α is 45 ° according to the embodiment of the present invention.
= 45 ° lock torque characteristic. )
This is smaller than the peak value of the lock torque characteristic when the inclination angle α = 0 °, which is a conventional example (hereinafter, referred to as the lock torque characteristic when α = 0 °). However, the value near the peak of the lock torque characteristic at α = 45 ° was necessary and sufficient for the lock mechanism of the actuator 1. Therefore, when the actuator 1 was not operated, the actuator 1 was sufficiently locked as in the conventional example. In addition, since the peak value of the lock torque is not excessive, as apparent from FIG. 9, when the rotation angle of the actuator 1 is smaller than that of the conventional example, the lock torque value becomes smaller than a predetermined value. That is, the range of the rotation angle of the actuator 1 in which the influence of the lock torque on the servo system of the actuator 1 can be controlled is widened.

In FIG. 9, only the case where the inclination angle α = 45 ° is compared with the conventional example. However, the advantages with respect to the conventional example are obtained even when the inclination angles α = 15 °, 30 °, 60 ° and 75 °. It was similar. This is also apparent from the fact that the lock torque characteristics of FIGS. 4 to 8 are similar to each other, including the magnitude. However, based on the tendency of the lock torque characteristic to change with respect to the change of the inclination angle α shown in FIGS. 4 to 8, when the inclination angle α is less than 15 ° or more than 75 °, the lock torque characteristic of the conventional example is closer. It is considered to be. Therefore, it is considered that the inclination angle α is desirably in the range of 15 ° to 75 ° in order to more clearly realize the advantages over the conventional example described above.

Further, in the actual measurement of the lock torque characteristic in the embodiment of the present invention, as shown in FIGS.
Is set in the range of 30 ° to 60 °, the variation in lock torque can be suppressed. In particular, when α = 45 °, the suppression was most effective. This is considered for the following reasons. 4 to 8, circles indicate the lock torque when the actuator 1 rotates from the inner circumference to the outer circumference, and triangles indicate the lock torque when the actuator 1 rotates from the outer circumference to the inner circumference. Indicates the actual measurement value. The curves in the figures are curves representing the lock torque characteristics obtained from the actually measured values, and the arrows indicate the direction of rotation of the actuator 1. In these figures, the variation in the positions of the circles and triangles indicating the actual measured values of the lock torque was obtained by repeating the measurement of the lock torque using the lock mechanism of the same actuator 1 a plurality of times. However, the position of the lock pin 2a was reset every measurement. The variation in the lock torque obtained by doing so was considered to be due to the deviation from the designed position of the lock pin 2a that occurred during the assembly of the lock mechanism.

The range of the rotation angle where the variation of the lock torque is most problematic is the rotation angle corresponding to the peak of the lock torque on the inner circumference of the magnetic disk 5 and the outer circumference of the curve showing the lock torque characteristic. It is considered to be a range intermediate between the rotation angle corresponding to a comparatively gentle area. It is considered that the control of the actuator 1 is possible even in consideration of the influence of the lock torque within this range, that is, the boundary of the range of the rotation angle that can be used as the recording area on the magnetic disk 5 exists. Because. As the value of the rotation angle included in the range of the rotation angle that causes the problem, for example, θ shown in FIGS. The variation of the lock torque at the rotation angle θ is relatively small when the inclination angle α is 30 ° to 60 ° from the variation of the actually measured values shown in FIGS. In particular, when the inclination angle α was 45 °, the variation was the smallest.

From the above, it was considered that the range of the inclination angle α of 30 ° to 60 ° was desirable for suppressing the variation of the lock torque. In particular, it was determined that the suppression was most effective near the inclination angle α = 45 °.

The reason why the lock torque characteristic becomes ideal when the inclination angle α is different from the conventional example of 0 ° is considered as follows.

At the time of locking the actuator 1, a case is considered in which the distance between the lock pin 2a and the lock magnet 8 at the closest point is fixed and the inclination angle α is changed.
Then, when the inclination angle α is different from 0 °, the amount of magnetic flux from the locking magnet 8 that penetrates the lock pin 2a becomes equal to the inclination angle α
It is considered that it decreases from the time when = 0 °. This indicates that the embodiment of the present invention exerts a smaller attractive force on the lock pin 2a of the lock magnet 8 than the conventional example. Therefore,
The peak value of the lock torque can be made necessary and sufficient without replacing the lock magnet 8 with a magnet having a weak magnetic force or reducing the volume of the lock pin 2a.

Further, it is considered that the amount of the magnetic flux is minimum when the inclination angle α is 45 °. Therefore, the peak value of the lock torque is considered to be minimum when the inclination angle α is 45 °. From this, in the range of the most problematic rotation angle described above, the slope of the curve indicating the lock torque characteristic is represented by the slope angle α =
It is considered to be the gentlest at 45 °. Because the distance between the lock pin 2a and the lock magnet 8 is sufficiently large in the outer peripheral portion of the magnetic disk 5 as compared with the length of the side forming the cross section of the lock pin 2a, the magnitude and shape of the lock torque characteristic are This is because it is considered that it does not depend much on the inclination angle α. If the slope of the curve indicating the lock torque characteristic is gentle, the rotation angle and the actual lock pin 2a
It is considered that the value of the lock torque does not greatly change if the correspondence between the distance and the distance to the locking magnet 8 is slightly shifted. Therefore, it is considered that when the inclination angle α is 45 °, the variation of the lock torque in the range of the rotation angle, which is the most problematic, can be suppressed most effectively.

Although the above embodiment is directed to a magnetic disk drive, the present invention can also be implemented as a lock mechanism for an actuator of a magneto-optical disk drive or the like.

As described above, according to the present invention, the lock torque characteristic is more ideal as compared with the conventional case where the lock pin 2 is attracted by the lock magnet 8 to lock the actuator 1. That is, the influence of disturbance on the servo system of the actuator 1 due to the attraction force of the locking magnet 8 is such that the influence on the servo system can be controlled.
Is wider than the conventional example. Therefore, it is possible to control the actuator 1 within a wider range of the rotation angle.

Further, the present invention can use a portion of the magnetic disk 5 that has not been used as a data area because of the large influence of the disturbance, as a data area. Therefore, the storage capacity of the magnetic disk 5 can be improved as compared with the conventional example.

The above effect is apparent when the inclination angle α between the lock pin 2a and the lock magnet 8 is 15 ° to 75 °.

When the inclination angle α is in the range of 30 ° to 60 °, the variation of the lock torque is obviously suppressed. Therefore, the control of the actuator 1 is facilitated to the extent that the variation from the lock torque characteristic assumed in advance in control is reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a lock mechanism of an actuator according to an embodiment.

FIG. 2 is an enlarged perspective view of a lock pin 2a and a lock magnet 8, which are main parts of a lock mechanism of the actuator according to the embodiment.

FIG. 3 is a schematic diagram of ideal and actual lock torque characteristics in a lock mechanism of a magnetic attraction type actuator (a broken line indicates ideal characteristics, a solid line indicates actual characteristics, and an arrow indicates the direction of rotation of the actuator). Shown.)

FIG. 4 is a lock torque characteristic diagram at an inclination angle of 15 ° in the lock mechanism of the actuator according to the embodiment (arrows indicate the rotation direction of the actuator 1; (The circle is shown when the magnetic disk 5 is from the inner periphery to the outer periphery, and the triangle is shown when the magnetic disk 5 is from the outer periphery to the inner periphery.)

FIG. 5 is a lock torque characteristic diagram at an inclination angle of 30 ° in the lock mechanism of the actuator according to the embodiment (arrows indicate the direction of rotation of the actuator 1; (The circle is shown when the magnetic disk 5 is from the inner periphery to the outer periphery, and the triangle is shown when the magnetic disk 5 is from the outer periphery to the inner periphery.)

FIG. 6 is a lock torque characteristic diagram at an inclination angle of 45 ° in the lock mechanism of the actuator of the embodiment (arrows indicate the direction of rotation of the actuator 1; (The circle is shown when the magnetic disk 5 is from the inner periphery to the outer periphery, and the triangle is shown when the magnetic disk 5 is from the outer periphery to the inner periphery.)

FIG. 7 is a lock torque characteristic diagram at an inclination angle of 60 ° in the lock mechanism of the actuator according to the embodiment (arrows indicate the direction of rotation of the actuator 1; (The circle is shown when the magnetic disk 5 is from the inner periphery to the outer periphery, and the triangle is shown when the magnetic disk 5 is from the outer periphery to the inner periphery.)

FIG. 8 is a lock torque characteristic diagram at a tilt angle of 75 ° in the lock mechanism of the actuator according to the embodiment (arrows indicate the direction of rotation of the actuator 1; (The circle is shown when the magnetic disk 5 is from the inner periphery to the outer periphery, and the triangle is shown when the magnetic disk 5 is from the outer periphery to the inner periphery.)

FIG. 9 is a comparison diagram of lock torque characteristics at an inclination angle of 45 ° (broken line) and 0 ° (solid line, equivalent to the conventional example) in the lock mechanism of the actuator of the embodiment (arrows indicate the rotation direction of the actuator 1). Shown.)

FIG. 10 is a perspective view of a lock mechanism of a conventional actuator.

FIG. 11 is an enlarged perspective view of a lock pin 2 and a lock magnet 8 which are main parts of a lock mechanism of a conventional actuator.

FIG. 12 is a lock torque characteristic diagram at an inclination angle of 0 ° in the lock mechanism of the actuator according to the embodiment of the present invention, which is regarded as equivalent to the conventional example (arrows indicate the direction of rotation of the actuator 1; actual measurement of lock torque); The value is indicated by a circle when the direction of rotation of the actuator 1 is from the inner periphery to the outer periphery of the magnetic disk 5, and is indicated by a triangle when the rotation direction is from the outer periphery to the inner periphery.)

[Explanation of symbols]

 Reference Signs List 1 actuator 2 lock pin (conventional example) 2a lock pin (example according to the present invention) 3 rotating shaft 4 voice coil motor 5 magnetic disk 6 magnetic head 7 suspension 8 locking magnet

Claims (4)

[Claims] 1. A head unit for recording or reproducing data on a recording medium, a carriage unit supporting the head unit and rotatably provided about a predetermined rotation axis as a fulcrum, and a carriage driving magnet A carriage driving means for rotating the carriage means to move the head means to a predetermined position on the recording medium; and a carriage driving means provided on the carriage means and substantially parallel to the rotation axis. An actuator that has a lock pin made of a magnetic member protruding in a desired direction, and that rotates when the operation is performed with the rotation axis as a fulcrum, and that the actuator is rotated by sucking the lock pin when the actuator is not operating. A locking mechanism of an actuator in a magnetic disk drive having a locking magnet installed so as to be locked. The cross-sectional shape of the lock pin substantially perpendicular to the direction in which the lock pin projects at a portion that intersects the magnetic flux of the lock magnet is polygonal, and the lock pin is not operated when the actuator is not operated. When the rotation of the actuator is locked by being attracted to the locking magnet, the lock pin is locked in the polygonal shape.
A locking mechanism for an actuator, wherein the vertical angle is set so as to contact or approach the locking magnet. 2. The locking mechanism according to claim 1, wherein the polygon is a quadrangle whose apex angle in contact with or close to the locking magnet is substantially a right angle. 3. An angle between one surface forming an apex angle of the lock pin in contact with or in proximity to the lock magnet and a surface in contact with or in proximity to the lock pin of the lock magnet is 15 ° to 75 °. The locking mechanism for an actuator according to claim 2, wherein: 4. An angle between one surface forming an apex angle of the lock pin and a surface of the lock magnet which is in contact with or close to the lock pin is 30 ° to 60 °. 3. The locking mechanism of the actuator according to 2.