JPH04109466A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To improve reliability by arranging a shock absorbing member on the same plane as the working plane of an actuator, and making a flexible part formed at a part of it capable of coming into contact with a part of the actuator and in addition, capable of being held as being engaged with a part of a voice coil motor. CONSTITUTION:The cushioning member 8 is arranged on the nearly same plane as the working plane of the actuator 1, and in addition, a part of it has flexibility, and the flexible part 8b is made capable to abut on a part of the actuator 1, and in addition, it is held by being engaged with a fixed part of the voice coil motor. Accordingly, when the actuator 1 runs away to B direction, a pressing part 1d formed at the end of an arm part 1b abuts on the flexible part 8b of the cushioning member 8, and after that, the flexible part 8b is bent by DELTAx by the portion of run-away energy the actuator 1 has obtained, and the run-away energy is absorbed. Thus, the higher reliability can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a magnetic disk drive, and more particularly to a stop device for a head drive actuator that positions a magnetic head.

[Prior Art 1] As a conventional stop device for a head drive actuator, the structure disclosed in Japanese Utility Model Application Publication No. 62-83265 is generally known, and more details are shown in FIGS. 5 and 6. Shown below.

FIG. 5 is a partially exploded, partially sectional plan view showing a conventional stopping device, and FIG. 6 is a view taken in the direction of arrow A in FIG.

In FIGS. 5 and 6, 51 is an arm, and the arm 51 has a flat moving coil 52 fixed to one end and a magnetic head (not shown) fixed to the other end.
2 is rotatably disposed via a shaft 53 so that it is located within the cavity 61.

The magnet 62 also has an upper yoke 63 and a lower yoke 64.
The movable coil 52 is fixed to the movable coil 52 by adhesive or other means, and is disposed at a position facing the movable coil 52.

Further, the upper yoke 63 and the lower yoke 64 are connected by yoke spacers 65a and 65b to form a magnetic circuit unit 66.

Here, stoppers 67a and 67b made of urethane rubber for regulating the operating range of the arm 51 are fitted into parts of the yoke spacers 65a and 65b.

In the head drive actuator adopting the configuration described above, when a signal current is applied to the movable coil 52,
According to Fleming's left-hand rule, a driving force is applied to the movable coil 52 around the shaft 53, causing the arm 51 to rotate and moving the magnetic head fixed to the arm 51 onto a magnetic disk (not shown). Position it on the desired recording track.

Further, if an accidental failure such as an error in reading position information or a failure in the actuator drive circuit occurs in the head drive actuator, the actuator may cause a so-called runaway operation other than the permissible operation.

When this runaway operation occurs, the rotation of the actuator is stopped by the urethane rubber acid stopper 67a or 67b, thereby preventing the movable part of the actuator from moving beyond a predetermined range.

Generally, in this type of actuator, in order to secure a large information recording area on the magnetic disk surface, it is desirable that the distance for stopping the actuator's runaway operation be as small as possible.

In addition, in order to prevent the magnetic head moved by the actuator from coming into contact with the magnetic disk when stopping a runaway state, the acceleration applied to the actuator, or even the magnetic head, when the actuator stop device is activated is allowed. It is required to be less than or equal to the value.

1. Problems to be Solved by the Invention] However, the above-mentioned conventional technology has the following problems.

First, in order to stop the runaway state of the actuator, the runaway energy must be efficiently absorbed.

Therefore, in the prior art as shown in FIGS. 5 and 6, when stopping the runaway state of the actuator, sufficient elastic deformation must be caused in the urethane rubber acid stoppers 67a and 67b.

For this purpose, it is necessary to compress the rubber to an order of a fraction of its thickness, which necessitates increasing the mounting volume. In other words, the amount of displacement of the rubber must be large in order to absorb the runaway energy.

The normal operating range of the actuator is θ shown in Figure 5.
Therefore, the operating range of the magnetic head is also θ.

If the amount of displacement of the rubber is set to be large, θ will inevitably become small, and the recordable area on the magnetic disk will be limited to a small size, resulting in a problem that the information recording capacity will be reduced.

Furthermore, the device itself has become larger, which is contrary to the current demand for light, light, short, and small vinegar.

Furthermore, if the mounting volume of the rubber is sacrificed in pursuit of miniaturization, runaway energy cannot be absorbed sufficiently, and the actuator cannot reduce the acceleration applied to the magnetic head. There was a high possibility that it would cause a crash.

Furthermore, since the stopper is made of rubber, its shape changes greatly in response to temperature changes within the magnetic disk drive, resulting in a lack of dimensional stability.

Next, rubber materials generally have a significantly higher oil content than other mechanical component materials such as metals and resins.

Therefore, if a rubber material is used in a magnetic disk device, the oil contained inside will scatter in response to environmental changes or changes over time within the device, and as a result, it will adhere to the magnetic disk, causing the magnetic There is a high possibility that adhesion between the head and the magnetic disk, a head crash, or an increase in defects due to disk corrosion will occur.

Therefore, the present invention is intended to solve the various problems mentioned above.The purpose of the present invention is to have a stop device that has a small mounting volume, efficiently absorbs the runaway energy of the actuator, and guarantees even higher reliability. The purpose is to provide a compact magnetic disk device.

Means for Solving Lesson 1 1 In order to solve the above problems, a magnetic disk device according to the present invention includes at least one magnetic disk and at least one magnetic disk that faces the magnetic disk and achieves recording and reproduction of information. A magnetic disk drive comprising: a magnetic head; an actuator that supports and moves the magnetic head; a voice coil motor that drives the actuator; and a buffer member that buffers and stops the actuator. The actuator is disposed within a substantially concave surface of the actuator, and at least a portion thereof is flexible, and the flexible portion is capable of contacting a portion of the actuator, and the voice coil motor is It is characterized by being held by engaging with a fixed part.

[Example 1] Hereinafter, a preferred example according to the present invention will be described in detail.

FIG. 1 is a partially broken sectional plan view showing a magnetic disk device to which the present invention is applied, and FIG. 2 is an enlarged view of the main part in FIG.

3 is a sectional view of a main part in FIG. 2, and FIG. 4 is a sectional view of another main part in FIG.

1 to 4, an actuator 1 has a magnetic head 3 fixed to one end for recording and reproducing information on a magnetic disk 2, and a movable coil 4 forming part of a voice coil motor fixed to the other end. , are rotatably arranged via a shaft 11.

Further, a lower yoke 5 and an upper yoke 6 are arranged at both ends of the movable coil 4 facing each other in the three-dimensional direction, and are connected by yoke spacers 7a and 7b.

Furthermore, a magnet 10 is fixed to the movable coil 4 side of the upper yoke 6 by means of adhesive or the like to constitute a magnetic circuit unit.

Here, the yoke spacers 7a and 7b have a stepped hollow cylindrical shape as shown in FIGS. 3 and 4, and have a small diameter part 31 and a medium diameter part 32.

By the way, as shown in FIG. 1, the arm portions 1a and 1b of the actuator 1 that sandwich the movable coil 4 become thinner in the middle, and the ends of the arm portions 1a and 1b have a substantially half-moon-shaped pressing portion IC11d. are integrally formed.

On the other hand, as shown in FIGS. 2 to 4, the buffer member 8 made of, for example, a plastic material is connected to the yoke spacer 7b.
It has an opening 8a that fits into the middle diameter part 32 of the middle diameter part 3.
2 and is secured and held.

Furthermore, substantially both ends of a portion of the opening 8a extend outward,
Beam-shaped flexible parts 8b each curved and combined to have flexibility
is formed.

Further, there is a hollow space between the front of the flexible part 8b and the part where the stand is held.

Furthermore, a protrusion 8C is integrally formed on the abutting member 8, an opening 42 is provided in the lower yoke 5, and the pressing portion 1d and the flexible portion 8b are arranged in a desired positional relationship. The protrusion 8C is fitted into the protrusion 8C so as to make contact with the protrusion 8C.

In addition, here l! Although the structure around the buffer member 8 has been described in detail, the structure around the buffer member 9 shown in FIG. 1 is also exactly the same as described above.

In the magnetic disk drive according to the present invention described in detail above, when a signal current is applied to the movable coil 4, a driving force acts on the movable coil 4 around the shaft 11 according to Fleming's left hand rule, and the actuator 1 is rotated to position the magnetic head 3 fixed to the actuator 1 at a desired recording track on the magnetic disk 2.

Next, a case where an accidental failure such as an error in reading position information or an actuator drive circuit failure occurs in the magnetic disk device according to the present invention, that is, a case where a so-called runaway operation other than the permissible operation of the actuator occurs will be described.

In FIG. 2, consider a case where the actuator 1 runs out of control in the direction B in the figure.

In this case, first, the pressing portion 1d provided at the end of the arm portion 1b of the actuator 1 comes into contact with the flexible portion 8b of the buffer member 8.

Thereafter, the flexible portion 8b is bent by ΔX corresponding to the runaway energy obtained by the actuator 1, and the runaway energy is absorbed.

Here, a moment is applied to the buffer member 8 around the center 0 of the opening 8a, which is indicated by the intersection of two dashed lines in FIG. 2, and a rotating force is applied to the yoke spacer 7b. act.

However, the protrusion 8c and the opening 42 of the lower yoke 5 engage with each other, and also serve as a rotation prevention means 43 for the buffer member 8.

Therefore, the flexible portion 8b of the buffer member 8 does not rotate and is deflected in the manner shown by the two-dot chain line in FIG. 2, efficiently absorbing the runaway energy.

Further, a part of the flexible portion 8b side on the outer circumferential side of the opening 8a of the buffer member 8 has a cylindrical surface 8 concentric with the opening 8a.
d, and serves as a stopper for the flexible portion 8b.

That is, if the runaway energy of the actuator 1 is greater than expected and the flexible portion 8b is bent too much, in the worst case, the flexible portion 8b will stop at the cylindrical surface 8d, preventing damage to the buffer member 8. to prevent.

The magnetic disk device according to the present invention described in detail above has the following advantages.

FIG. 7 is a diagram showing the difference in buffer efficiency between the conventional example and the embodiment according to the present invention.

In the figure, the horizontal axis represents the displacement of the stopping device during shock absorption, and the vertical axis represents the load applied to the device. When a rubber material serves as a stop device as in the conventional example, its load-displacement characteristics are as shown by F(x) in the figure.

On the other hand, in this embodiment, it becomes G(x).

Assuming that the displacement of the stopping device when it absorbs the impact energy reaches xi, the degree of impact energy absorption of the device can be expressed by integrating each of F (x) and G (x) up to xi in the figure.

Therefore, the embodiment according to the present invention is larger than the conventional example by 8 times the area surrounded by the straight line ON and the arc ON shown by diagonal lines in the figure.

Therefore, the stopping device of this embodiment can absorb large impact energy with a small amount of displacement.

In other words, it is possible to effectively absorb impact energy with a small mounting volume.

Therefore, the operating range of the magnetic head 3 fixed to the actuator 1 can be increased, and a large recordable capacity on the magnetic disk 2 can be secured.

It also greatly contributes to the miniaturization of devices.

Furthermore, since a plastic material such as polyacetal is used as the buffer member, there is no fear of gas generation, and the inside of the magnetic disk drive is always kept clean.

As a result, there is no adhesion between the magnetic disk and the magnetic head, head crashes, defects due to disk corrosion, etc., resulting in an extremely high-performance magnetic disk device.

Furthermore, since the buffer member of this embodiment is made of plastic, it can be mass-produced and is easy to assemble, resulting in low parts and assembly costs, and therefore can be provided at low cost.

Furthermore, dimensional stability is also significantly improved.

In this example, the shape of the flexible part of the m-plane member is illustrated as being beam-like, but it is of course not limited to this and can be freely set as long as it does not depart from the gist of the present invention. .

[Effects of the Invention 1] As described above in detail, the magnetic disk drive according to the present invention has a buffer member for stopping the actuator in the same plane as the operating surface of the actuator, and at least a portion thereof is flexible. Since the flexible portion can come into contact with a part of the actuator and is held in engagement with a part of the voice coil motor, the mounting volume of the buffer member can be reduced, and the actuator impact energy can be absorbed with high efficiency.

Furthermore, the operating range of the magnetic head fixed to the actuator can be increased, and a large information recording capacity on the magnetic disk can be secured.

At the same time, by effectively utilizing the space inside the magnetic disk drive,
This can greatly contribute to making equipment smaller and thinner, which is desired by consumers these days.

Furthermore, since the buffer member is made of plastic, there is no generation of harmful gases, etc., and as a result, the atmosphere inside the magnetic disk drive is always kept clean, preventing adhesion between the magnetic head and the magnetic disk, head crashes, or disk failure. The practical effects of the present invention are extremely large, such as providing a magnetic disk device with extremely high performance and reliability without defects caused by corrosion.

[Brief explanation of drawings]

FIG. 1 is a partially broken sectional plan view showing a magnetic disk device to which the present invention is applied. Figure 2 is an enlarged view of the main parts in Figure 1. FIG. 3 is a sectional view of the main part in FIG. 2. FIG. 4 is a sectional view of another important part in FIG. 2. FIG. 5 is a partially exploded, partially sectional plan view showing a conventional stopping device. FIG. 6 is a view taken along arrow A in FIG. FIG. 7 is a diagram showing the difference in buffer efficiency between the conventional example and the embodiment according to the present invention. 1...Actuator 2...Magnetic disk 3...Magnetic head 8.9...Buffer member 8b...Flexible part 43...・Applicant for anti-rotation means and more Seiko Epson Co., Ltd. Agent Patent attorney Kizobe Suzuki and 1 other person Figure 3 Figure 4 $ Akira;

Claims (5)

[Claims] (1) At least one magnetic disk, at least one magnetic head that faces the magnetic disk to achieve information recording and reproduction, an actuator that supports and moves the magnetic head, and drives the actuator. In a magnetic disk drive comprising a voice coil motor and a buffer member for buffering and stopping the actuator, the buffer member is disposed in substantially the same plane as the operating surface of the actuator, and at least a portion thereof is flexible. 1. A magnetic disk drive, wherein the flexible part is capable of contacting a part of the actuator and is held by engaging with a fixed part of the voice coil motor. (2) Claim 1, wherein the buffer member has a hollow portion between a portion that contacts a portion of the actuator and a portion that engages with a fixed portion of the voice coil motor. The magnetic disk device described. (3) The magnetic disk device according to claim 2, wherein the buffer member is made of a plastic material. (4) The magnetic disk device according to claim 2, wherein the buffer member is integrally provided with at least a part of rotation prevention means for preventing rotation. (5) The magnetic disk device according to claim 2, wherein the buffer members are arranged at both ends of movement of the actuator.