JP2003228956A - Disk unit with noise reduction mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disk unit having a noise reduction mechanism which can maintain a low noise by making the head of the disk unit seek at a high speed. <P>SOLUTION: The disk unit has a base housing 10 having a space storing a disk 16 and the head 40, a cover 12 which closes the space storing the disk 16 and head 40 together with the base housing 10, a vibration sensor 201 which is fitted to the cover 12 and detects vibrations of the cover 12, an actuator 202 which is fitted to the cover 12 and vibrates the cover 12 with its own vibrations, and a vibration control means 205 for vibrating the actuator 202 to cancel vibrations of the cover 12 detected by the vibration sensor 201. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc device having a noise reduction mechanism for reducing noise caused by vibration generated in a cover of the disc device.

[0002]

2. Description of the Related Art A so-called magnetic disk device (hereinafter referred to as HDD), which is one of the disk devices, has been used as an external storage means of a computer or the like while continuing to achieve higher density and higher speed. However, in recent years, it is being used as a general home electric appliance such as a car navigation system and a video system because of its high density and high speed and a low bit unit price per storage capacity. When an HDD is used as such a general home electric appliance, not only high density and high speed but also low noise are demanded.

In an HDD, a lot of noise may be generated from a head assembly and a voice coil motor (hereinafter, referred to as VCM) that drives the head assembly during so-called seek operation in which the head is moved to a target track on the disk. Even when the HDD is used for the general household products as described above, a technique for realizing low-noise and high-speed seek has become important.

The noise reduction technology for HDDs is broadly described in the following 2
Two methods are considered. One is a seek control technique that does not excite the mechanical resonance of the head assembly (actuator). In this seek control technique, the control current does not include many components at the mechanical resonance frequency of the head assembly (actuator).
Specifically, a method using a control input that minimizes jerk (jerk) such as a SMART (self-monitoring analyzing report function: failure prediction function by the HDD itself), or a feed-forward control input during seek. There is a method of applying a smooth control command to the actuator by shortening the cycle applied to the actuator to less than the feedback control cycle.

The other is mechanical technology. For example, by increasing the mechanical resonance frequency of the head assembly (actuator) as much as possible to make it less likely to be excited during seek, or by making the HDD top cover in a state similar to what is called a speaker, noise during seek of the head assembly (actuator) is transmitted to the outside. There is a method of adding a damping plate to the top cover so that it will not be transmitted to.

Regarding the above-mentioned seek control technique, Japanese Patent Laid-Open No. Hei 3
It is disclosed as prior art in Japanese Patent Laid-Open No. 102683, and is generally known.

[0007]

However, in the above-mentioned prior art, it is becoming difficult to realize a low noise and high speed seek from the following points. First, in order to realize high-speed seek, it is necessary for the control command to have a component up to a high frequency band, and it is very difficult to avoid excitation of mechanical resonance of the head assembly (actuator).
Further, it is becoming very difficult to increase the mechanical resonance of the head assembly (actuator) more than it is now. Furthermore, it is becoming difficult to add sufficient vibration suppression (damping) to the vibration mode of the top cover simply by attaching the damping plate to the top cover.

Therefore, an object of the present invention is to solve the above problems, and to provide a disk device having a noise reduction mechanism capable of maintaining low noise even when the head seeks at high speed. is there.

[0009]

In order to achieve the above object, a disk device according to the present invention is a disk device for reproducing information from a head on a disk, and a housing for housing the disk and the head, and the disk. And a cover for closing the head, a vibration sensor attached to the cover for detecting vibration of the cover, an actuator attached to the cover for vibrating the cover by its own vibration, and detected by the vibration sensor. And a vibration control means for vibrating the actuator so as to cancel the vibration of the cover.

According to the above-described structure, the output of the vibration sensor attached to the cover is fed back to the actuator also attached to the cover, so that the vibration of the cover detected by the vibration sensor, that is, the head assembly (actuator). It is possible to suppress the vibration that is transmitted from the to the cover and to reduce the noise when the head assembly (actuator) seeks.
Then, it is possible to provide a disk device having a noise reduction mechanism capable of maintaining low noise even when the head is sought at high speed.

Further, the vibration sensor of the disk device according to the present invention is mounted at a plurality of positions of the cover, and detects vibrations corresponding to individual vibration frequencies at a plurality of positions of the cover. The actuator includes a plurality of actuators attached to a plurality of positions of the cover and vibrating the plurality of positions of the cover at individual frequencies, and the vibration control unit is detected by the plurality of vibration sensors. In addition, the plurality of actuators are vibrated so as to cancel vibrations at a plurality of positions of the cover.

According to such a configuration, the outputs of the vibration sensors attached to a plurality of positions on the cover are fed back to the actuators attached to a plurality of positions corresponding to the vibration sensors on the cover as well, so that each vibration is transmitted. Vibration of a plurality of frequency components generated in the cover detected by the sensor, that is, vibration of a plurality of frequency components transmitted from the head assembly (actuator) to the cover can be suppressed, and seek of the head assembly (actuator) can be suppressed. It is possible to achieve low noise at times. And
It is possible to provide a disk device having a noise reduction mechanism capable of maintaining low noise even when the head is sought at high speed.

Further, in the disk device according to the present invention, a disk having a track on which information can be recorded, a head for recording and reproducing information on the track of the disk, and a head which is rotatable about an axis are held. In addition, a head assembly that holds the head at the tip and has a coil at the other end, a drive unit that drives the coil of the head assembly, and a housing that has a space for housing the disk, the head, the head assembly, and the drive unit. A cover for closing the housing space together with the housing; a vibration sensor attached to the cover for detecting vibration of the cover; and vibration of the cover detected by the vibration sensor to resonate the head assembly. And a control hand for controlling the drive means so as to cancel the resonance of the head assembly. It is characterized in that it has provided and.

According to this structure, the output of the vibration sensor attached to the cover is fed back to the VCM driving the head assembly, so that the vibration of the cover detected by the vibration sensor, that is, from the head assembly (actuator). Vibration that is transmitted to the cover can be suppressed, and vibration suppression (damping) can be added to the main resonance of the head assembly (actuator), which is the source of noise, and noise reduction during seek is realized. It will be possible. Then, it is possible to provide a disk device having a noise reduction mechanism capable of maintaining low noise even when the head is sought at high speed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the disk device of the present invention is applied to a hard disk drive (hereinafter referred to as HDD) which is a magnetic disk device will be described in detail below with reference to the drawings.

FIG. 1 is an exploded perspective view showing the overall structure of the HDD according to this embodiment. As shown in FIG.
Is formed into a card shape, for example, PCMCIA type I
The thickness is 5.0 mm according to the I standard.
That is, as shown in FIG. 1, the HDD includes a base housing 10 in the shape of a rectangular plate made of metal.
Except for the peripheral edge, a recess is formed in which various members to be described later are mounted, and the upper surface side is open. Also, HD
D is a top cover 12, which is a plate-shaped cover member that closes the upper surface of the base housing 10, a printed circuit board 14 provided on the bottom surface side of the base housing 10, and a printed circuit board 1.
4 and a bottom cover 15 that covers the bottom surface side of the base casing 10, and by stacking these, a card-like shape is formed as a whole.

As shown in FIG. 1, a 1.8-inch magnetic disk 16 functioning as an information recording medium is provided in the concave portion of the base housing 10, and a spindle motor 18 as a drive motor for supporting and rotating the magnetic disk 16. , A plurality of magnetic heads 40 for writing and reading information to and from the magnetic disk 16, a head actuator 22 that movably supports the magnetic heads 40 with respect to the magnetic disk 16, and the head actuator 22 is rotated and positioned. Voice coil motor (hereinafter referred to as VCM)
24, a ramp load mechanism 25 that holds the magnetic head 40 in a position separated from the magnetic disk when the magnetic head 40 moves to the outermost periphery of the magnetic disk 16, an inertial latch mechanism 26 that holds the head actuator 22 in the retracted position, and a head. A board unit 21 having an IC and the like, and a pack-shaped air filter 28 are housed.

The spindle motor 18 is fixed to the base casing 10, and the magnetic disk 16 is fixed to the spindle motor 18
Is coaxially fitted to a hub (not shown) and is held by a clamp spring 17. Then, the magnetic disk 16 is rotationally driven by the spindle motor 18 at a predetermined speed.

The head actuator 22 is fixed to the base housing 10 and has a bearing assembly 26, two arms 32 extending from the bearing assembly 26, and a magnetic head assembly extending from the tip of each arm 32. 36 and a support frame 44 extending from the bearing assembly 26 in the direction opposite to the arm 32 and supporting the voice coil.
The nuclear magnetic head assembly 36 includes an elongated plate-shaped suspension and a magnetic head 40 fixed to the tip of the suspension via a gimbal portion (not shown).

The magnetic disk 16 is located between the two arms 32 in a state where the head actuator 22 having the above-described structure is incorporated in the base casing 10. The pair of magnetic heads 40 face the upper surface and the lower surface of the magnetic disk 16, respectively, and sandwich the magnetic disk 16 from both sides. A predetermined head load is applied to each magnetic head 40 toward the surface of the magnetic disk 16 by the spring force of the suspension.

The voice coil fixed to the support frame 44 of the head actuator 22 is a base casing 1.
It is located between a pair of yokes 48 fixed on the upper surface of the zero ring, and constitutes the VCM 24 together with these yokes 48 and the magnets fixed to one of the yokes 48. Then, by energizing the voice coil, the head actuator 2
2 rotates between the retracted position and the operating position on the magnetic disk 16, and the magnetic head 40 is positioned on a desired track of the magnetic disk 16 at the operating position. Further, the head actuator 22 is restricted from excessive rotation beyond the retracted position by the stopper pin 50 provided on the yoke 48.

Each magnetic head 40 is electrically connected to the substrate unit 21 via a flexible cable 52. The board unit 21 has a connector 53 for connecting to the printed circuit board 14. Further, the base housing 10 is mounted with a connector 56 facing the connector 53 of the board unit 21 and located in the rectangular signal line insertion opening 54, and a connection connector 57 for connecting the HDD to an external device. ing. The connector 56 of the printed circuit board 14 is connected to the connector 53 provided on the board unit 21 in the base housing 10 through the signal line insertion opening 54 of the base housing 10.

In the base casing 10, a vent hole 5 for communicating the inside and outside of the base casing 10 is provided at one corner of the recess.
8 is formed, and the air filter 28 is arranged so as to face the ventilation hole 58. Then, by the ventilation hole 58,
The pressure difference between the inside and the outside of the base casing 10 is eliminated, and at this time, the air filter 28 prevents dust and the like from entering from the outside.

On the other hand, the HDD has a seal 60 for keeping the inside of the base casing 10 confidential. As shown in FIG. 1, the seal 60 includes a frame-shaped main body 62 formed in a shape corresponding to the peripheral portion of the base housing 10, and first, second, and third main bodies 62 protruding inward from the main body 62. The seal portions 63, 64, 65 are integrally provided.

The main body 62 is formed by vertically sandwiching it between thin metal sheets or sealing materials 67a and 67b as a shape fixing material. First to third seal portions 63, 6
Reference numerals 4 and 65 are formed only of the sealing material. If the shape of the seal 60 can be maintained, the entire seal may be formed of only the sealing material.

Next, the HD which is the first embodiment of the present invention
The noise reduction mechanism of D will be described in detail. As shown in FIG. 2, a vibration sensor 201 for detecting vibrations generated in the top cover 12 and a vibration for canceling the vibrations detected by the vibration sensor 201 are generated in the top cover 12. Actuator 20
Attach 2. Vibration sensor 201 and actuator 2
02 is attached to the top cover 12 at substantially the same position on the front and back sides with an adhesive or the like. Vibration sensor 201 and actuator 2
02 is attached to almost the same position on the back surface of the top cover 12, so that the corrosion can be established and the so-called vibration sensor 201 for canceling the vibration generated in the top cover 12 by the vibration sensor 201 is cancelled. It becomes easier to control the actuator 202 to generate vibrations of opposite phase.

Vibration sensor 201 and actuator 202
In order to attach the HDD to the HDD top cover 12, it is necessary to make the thickness as thin as possible.
It is desirable to form the actuator 202 and the actuator 202 in a thin film shape. Particularly, as a material thereof, polyvinylidene fluoride (P
VDF) can be used.

Polyvinylidene fluoride (PVDF) has the following features. First, since polyvinylidene fluoride (PVDF) detects the differential of the strain generated in itself, it is possible to add vibration suppression (damping) to the top cover 12 with a simple control system. Polyvinylidene fluoride (PVDF) is elastic and flexible and can be shaped into various shapes. Furthermore,
Top cover 12 separated for each vibration mode by changing the shape of polyvinylidene fluoride (PVDF)
The vibration suppression control can be performed, and stable control can be performed without exciting other modes.

Due to the above features, the top cover 12
By using polyvinylidene fluoride (PVDF) as the vibration sensor 201 for detecting the vibration of the top cover 12, it is possible to efficiently detect the vibration of the top cover 12 while having a structure for suppressing the size increase of the device. Become.
In addition, flexible polyvinylidene fluoride (PVDF

By using the above, polyvinylidene fluoride (PV
Since it becomes possible to attach DF), it becomes possible to use polyvinylidene fluoride (PVDF) as the actuator 202 by applying a voltage.

If it is necessary to generate sufficient force to suppress the vibration of the top cover 12 detected by the vibration sensor 201, polyvinylidene fluoride (P
Instead of using the VDF) actuator 202,
It is also possible to use a thin film piezo (PDT) element instead.

In this way, the HDD top cover 12
Further, a vibration sensor 201 for detecting the vibration generated in the top cover 12, and an actuator 202 for generating the vibration for canceling the vibration of the top cover 12 detected by the vibration sensor 201 in the top cover 12
By attaching, the vibration mode of the top cover 12 can be controlled.

In the above-described first embodiment of the present invention, for the single mode control of the top cover 12,
A system as shown in the circuit block diagram of FIG. 3 is constructed for the top cover 12 of the HDD, and a control system as shown in FIG. 4 is constructed. The control system of this embodiment constitutes a digital feedback control system.

An analog signal from the vibration sensor 201 attached to the top cover 12 is amplified by an amplifier 203, converted into a digital signal by an A / D converter 204, and then converted into an A / D signal by the A / D converter 204. The converted digital signal is a microprocessor (MPU) 2
It is taken in by 05. Then, a feedback control amount is calculated in the microprocessor (MPU) 205 from the captured digital signal, and the actuator 202 attached to the top cover 12 is driven through the driver 206.

At this time, the vibration generated in the top cover 12 is detected by the vibration sensor 201 attached thereto, and the microprocessor (MPU) 205 vibrates in a phase opposite to the phase of the vibration detected by the vibration sensor 201. Of the feedback control amount for generating the feedback control amount is calculated.
No. 02 is applied.

By executing such a series of digital feedback control, vibration suppression (damping) is added to the vibration generated in the top cover 12 detected by the vibration sensor 201 attached to the top cover 12. Is possible.

As a modification of the above-described first embodiment, it is possible to adopt a control system as shown in FIG. Microprocessor (MPU) installed in HDD
If the 205 does not have sufficient processing capacity, the same effect can be obtained by configuring an analog feedback system as shown in FIG. That is, when the vibration sensor 201 can detect the differential of the strain, a feedback controller having a constant gain near the frequency of the vibration mode of the top cover 12 can be used, and when the vibration sensor 201 detects the strain amount, It is possible to use the one having differential characteristics in the vicinity of the frequency of the vibration mode of the top cover 12.

Next, the contents of the second embodiment of the present invention will be described in detail with reference to FIG. In the second embodiment, a plurality of vibration sensors 201 are attached to the top cover 12 as shown in FIG. 6 so that it is possible to control a plurality of vibration modes generated on the top cover 12.
a-201d and actuators 202a-202d are attached. The vibration frequencies that can be detected by the respective vibration sensors 201a to 201d are different from each other, and by sticking these to the top cover 12 with an adhesive or the like, it is possible to detect the vibrations of a plurality of frequency modes generated in the top cover 12. It will be possible.

A control system according to the second embodiment of the present invention will be described with reference to FIG. The digital feedback control system used in the above-described first embodiment can be applied to the control system of the present embodiment. That is, the amplifier 2 outputs analog signals from the plurality of vibration sensors 201a to 201d.
03, and the amplified analog signal is A /
The D converter 204 converts the digital signal. The digital signal converted by the A / D converter 204 is taken into a microprocessor (MPU) 205, the feedback control amount of the digital signal is calculated inside the microprocessor, and the top cover 1 is passed through a plurality of drivers 206.
The plurality of actuators 202a-2 attached to
Drive 02b.

By executing such a series of digital feedback control, it becomes possible to add vibration suppression (damping) to a plurality of vibration modes of the top cover 12.

As a modification of the above-described second embodiment, it is possible to adopt a control system as shown in FIG. Microprocessor (MPU) installed in HDD
If 205 does not have sufficient processing capacity, the same effect can be obtained by configuring an analog feedback system as shown in FIG. That is, when the vibration sensor 201 can detect the differential of the strain, a feedback controller having a constant gain near the frequency of the vibration mode of the top cover 12 can be used, and when the vibration sensor 201 detects the strain amount, It is possible to use the one having differential characteristics in the vicinity of the frequency of the vibration mode of the top cover 12.

Next, the contents of the third embodiment of the present invention will be described in detail with reference to FIG. In the third embodiment, the vibration sensor 20 attached to the top cover 12
In No. 1, vibration can be detected by the main resonance of the head assembly (actuator) 22. The control system of this embodiment constitutes a control system as shown in FIG.

By constructing such a control system,
Vibration suppression (damping) can be added to the main resonance of the head assembly (actuator) 22 that is the source of noise in the HDD, and noise during head seek can be reduced. A block diagram of the control system at this time is shown in FIG. The output from the vibration sensor 201 does not directly detect the resonance mode of the arm of the head assembly (actuator) 22. Therefore, the feedback controller has a function of correcting the output of the vibration sensor 201.

Although the HDD, which is a magnetic disk device, has been described as an example in the present embodiment, the present invention is not limited to this. Even in an optical disk device such as a CD-ROM drive or a DVD drive, it is needless to say that similar effects can be obtained by using the structure in which the vibration sensor and the actuator are arranged on the top cover to suppress vibration as described above. .

[0045]

As described in detail above, according to the present invention,
The output of the vibration sensor attached to the cover is fed back to the actuator also attached to the cover to suppress the vibration of the cover detected by the vibration sensor, that is, the vibration generated by being transmitted from the head assembly (actuator) to the cover. Therefore, it is possible to reduce the noise when the head assembly (actuator) seeks. Further, it is possible to provide a disk device having a noise reduction mechanism capable of maintaining low noise even when the head is sought at high speed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an HDD according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the top cover according to the embodiment of the present invention.

FIG. 3 is a block diagram according to the first embodiment of the present invention.

FIG. 4 is a control block diagram for explaining a control system according to the first embodiment of the present invention.

FIG. 5 is a control block diagram for explaining a control system according to a modified example of the first embodiment of the present invention.

FIG. 6 is a block diagram according to a second embodiment of the present invention.

FIG. 7 is a control block diagram for explaining a control system according to a second embodiment of the present invention.

FIG. 8 is a control block diagram for explaining a control system according to a modified example of the second embodiment of the present invention.

FIG. 9 is a block diagram according to a third embodiment of the present invention.

FIG. 10 is a control block diagram for explaining a control system according to a third embodiment of the present invention.

[Explanation of symbols]

10 ... Base housing 12 ... Top cover 14 ... Printed circuit board 15 ... Bottom cover 16 ... Magnetic disk 18: Spindle motor 21 ... Board unit 22 ... Head actuator 24 …… VCM 25: Lamp lead mechanism 50 …… Stopper pin 53, 56 ... Connector 54: Signal line insertion opening 58 ... Vent hole 60 …… Seal 62 ... Main body 201a, b, c, d ... Vibration sensor 202a, b, c, d ... Actuator 203 ... Amplifier 204, 207 ... A / D converter 205: Microprocessor (MPU) 206 …… Driver

Claims (10)

[Claims] 1. A disc device for reproducing information from a disc by a head, a casing for accommodating the disc and the head, a cover for closing the casing for accommodating the disc and the head, and a cover attached to the cover, A vibration sensor that detects the vibration of the cover; an actuator that is attached to the cover and vibrates the cover; and a vibration control unit that vibrates the actuator so as to cancel the vibration of the cover detected by the vibration sensor, A disk device characterized by being provided. 2. The cover has an inner surface facing the housing and an outer surface facing the outside of the housing, and the vibration sensor and the actuator sandwich the cover between the housing outer surface and the housing. 2. The disk device according to claim 1, wherein the disk device is attached at a position substantially opposite to the inner surface of the body. 3. The disk device according to claim 1, wherein the vibration sensor is made of polyvinylidene fluoride (PVDF) formed in a thin film shape. 4. The disk device according to claim 1, wherein the actuator is made of polyvinylidene fluoride (PVDF) formed in a thin film shape. 5. The disk device according to claim 1, wherein the actuator is formed of a piezoelectric element formed in a thin film shape. 6. An amplifier for amplifying a signal from the vibration sensor, a control amount of the actuator is calculated based on the amplified signal from the amplifier, and a control signal based on the control amount is fed back to the actuator. 2. The disk device according to claim 1, further comprising a vibrating microprocessor. 7. The vibration sensor includes a plurality of vibration sensors attached to a plurality of positions of the cover to detect vibrations corresponding to individual vibration frequencies of the plurality of positions of the cover, and the actuator includes: A plurality of actuators attached to a plurality of positions of the cover and vibrating the plurality of positions of the cover at individual frequencies, the vibration control unit includes a plurality of positions of the cover detected by the plurality of vibration sensors. 2. The disk device according to claim 1, wherein the plurality of actuators are vibrated so as to cancel the vibrations of the respective actuators. 8. A disc having a track on which information is recorded, a head for reproducing information from the track of the disc, rotatably held about an axis, and holding the head at the tip, A head assembly having a coil at an end, a driving means for driving the coil of the head assembly, a housing for housing the disk, the head, the head assembly and the driving means, a cover for closing the housing, and a cover. A vibration sensor attached to detect the vibration of the cover, and a vibration of the cover detected by the vibration sensor, calculates resonance of the head assembly, and controls the drive unit to cancel the resonance of the head assembly. A disk device, comprising: 9. The cover has an inner surface facing the housing and an outer surface facing the outside of the housing, and the vibration sensor and the actuator sandwich the cover between the outer surface of the housing and the housing. 9. The disk device according to claim 8, wherein the disk device is attached to a position substantially opposite to the inner surface of the body. 10. The disk device according to claim 8, wherein at least one of the vibration sensor and the actuator is formed of polyvinylidene fluoride (PVDF) formed in a thin film shape.