JPH03100976A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To securely and stably position a magnetic head by bonding a metalic antiresonance mass substance in interposition of a viscoelastic material to a flat spring for supporting both ends of a center shaft for supporting rotatably the magnetic head via a bearing. CONSTITUTION:When a coil 9 is suddenly moved by call and write commands, the flat springs 7a and 7b for bearing a movable part, such as the magnetic head 1, etc., is oscillated due to the above exciting force. By this oscillation, a relative positional change between the head 1 and an information position of a magnetic disk 15, i.e., an off-track is generated. However, since the flat springs 7a and 7b are bonded with the massive body 6 via the viscoelastic material 16, this massive body 6 is worked with a phase difference from an oscillation period, and this oscillation energy is transmitted to the viscoelastic material 16 to be substituted for thermal energy, thus diminishing the oscillation of the flat springs 7a and 7b.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device that prevents resonance in a portion that supports a magnetic head or a magnetic disk.

[Prior Art] In a magnetic disk drive, when there is a request to retrieve specific information recorded on a magnetic disk, the magnetic head is rapidly moved in the radial direction of the magnetic disk in order to minimize the retrieval time. We are determining its position. FIG. 3 is a longitudinal cross-sectional view of a conventional magnetic disk device, in which a magnetic helad l is supported by an arm 2, and the arm 2 is connected to both ends of the magnetic disc via a holder 3, bearings 4a, 4b, and a central shaft 5. were supported and fixed to the housings 12a and 12b by plate springs 7C, respectively.

Then, the magnetic helad l rotates around the central axis 5 and moves to an appropriate position on the magnetic disk 15, and as the magnetic disk 15 rotates around the spindle axis 14,
Predetermined magnetic data was written and read.

A voice coil motor coil (hereinafter referred to as a coil) 9 is attached to the arm 2 that supports the magnetic herad 1, and by passing a current through the coil 9, a permanent magnet l
The structure is such that a force is generated between O and the coil 9, and this causes the magnetic heald 1 to rotate. The positioning of the magnetic head 1 is usually performed by detecting the position of the magnetic head 1 → voice coil motor control circuit (not shown) → energizing the coil 9 → moving the coil 9 → moving the magnetic head 1 → detecting the position of the magnetic head 1. It is controlled by a servo circuit system that forms a closed loop.

In this case, the plate spring 7C supporting the central shaft 5 has an unnecessarily high rigidity, considering the pressing force against the central shaft 5, the degree of elastic deformation of the flat spring 7c, the strength of the screw 8 and the housings 12a and 12b, etc. It is inappropriate and usually
The thickness ranges from 1 to 2 mm and the length ranges from 5 to 20 mm, and the material is limited to spring steel and steel.

Problems to be Solved by the Invention] However, the conventional structure described above has the following problems. That is, due to the weight of the movable part, the spring constant of the leaf spring 7C, etc., the movable part including the magnetic head l contains several hundred [H
z] occurs. Since this low band resonance point oscillates when the aforementioned servo loop is in operation, there is a problem in that accurate positioning of the magnetic head l cannot be performed.

Further, the spindle shaft 14 that supports the magnetic disk 15 also has a
As with the central axis, when the above-mentioned support method is adopted, exactly the same problem occurs.

Furthermore, in the past, the recording density of magnetic disks was low and there was sufficient margin for reading and writing information, but as recording density and capacity have increased in recent years, there is no margin for reading and writing information, and the resonance occurs. Increasing the frequency or lowering the vibration level has become essential for accurate positioning of magnetic heads.

The present invention has been made by focusing on the above-mentioned conventional problems, and by solving these problems, it is possible to easily control the servo system and provide a magnetic disk that allows reliable and stable positioning of the magnetic head. We aim to provide the following.

To this end, the present invention provides a central shaft that rotatably supports a magnetic disk assembly formed by stacking a plurality of magnetic disks or a magnetic head assembly having a plurality of magnetic heads supported by an arm through a bearing. having both ends of the central axis,
In a magnetic disk drive in which the central shaft is supported and fixed to the housing by being pressed by a leaf spring and brought into pressure contact with a part of the housing, a viscoelastic material is provided between the leaf spring and the leaf spring. A metal resonance-preventing mass body is bonded with the intervening. Further, the rigidity of each of the above-mentioned leaf springs is made to be different from each other to prevent resonance.

[Example] Next, the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of an embodiment of the present invention. FIG. 2 is an enlarged plan view of section A in FIG. 1.

A magnetic disk device according to the present invention includes a magnetic disk assembly in which a plurality of magnetic disks 15 are stacked and supported on a spindle shaft 14, and a magnetic head assembly including a plurality of magnetic heads 1 supported on an arm 2. It has

In FIG. 1, 11 is a magnetic circuit consisting of a permanent magnet lO and a coil 9. Reference numeral 3 denotes a holder operated by the magnetic circuit 11. A plurality of rod-shaped arms 2 are attached to the side surface of the holder 3, and a magnetic head 1 is attached to the tip of the arm 2. The arm 2 has a central axis 5
The central shaft 5 is rotatable by plate springs 7a and 7b screwed to the housings 12a and 12b in recesses of a housing 12a that covers the upper part of the magnetic circuit 11 and a housing 12b that covers the lower part of the housing 12a. is bearing on the shaft,
Further, the holder 3 has bearings 4a and 4b on the central shaft 5.
Supported through.

15 is a magnetic disk, and the spindle shaft 1 is supported on the substrate 13 via a bearing (not shown) as described above.
Rotate around 4.

Further, a viscoelastic material 16 is provided on the surface of the leaf springs 7a and 7b.
A metallic mass body 6 is bonded via the metal body 6.

Next, its operation will be explained.

When the coil 9 moves rapidly in response to a read or write command, the excitation force causes the leaf springs 7a and 7b that support the movable parts of the magnetic head 1 to vibrate.This vibration causes the magnetic head 1 and the magnetic disk to vibrate. 15 information positions, that is, an off-track occurs. However, since the mass body 6 is bonded to the plate springs 7a and 7b via the viscoelastic material 16, the mass body 6 moves with a certain phase difference with respect to the cycle of the vibration, and the vibration energy is absorbed by the mass body 6. is transmitted to the viscoelastic material 16 and replaced with thermal energy, so that the above-mentioned leaf spring 7
The vibrations of a and 7b are significantly reduced. In addition, the central axis 5
By making the rigidities of the leaf springs 7a and 7b that support both ends of the leaf springs 7a and 7b different from each other and making the resonance points of the leaf springs 7a and 7b different from each other, the resonance phenomenon between the leaf springs 7a and 7b is effectively can be prevented.

Further, although this embodiment shows an example of a carriage system of a magnetic disk device, the above-mentioned problem can be solved by using a spindle shaft that supports a magnetic disk with a similar structure.

[Effects of the Invention] As explained above, the present invention has a central shaft that rotatably supports a magnetic head etc. via a bearing, and a plate spring that supports both ends of the central shaft. A metal resonance-preventing mass body is bonded with a viscoelastic material interposed between them, and the rigidity of the leaf springs is made to be different from each other as necessary, so that during writing and reading operations of the magnetic head. Another advantage is that servo loop oscillation can be prevented and a highly reliable magnetic disk device can be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the magnetic disk device of the present invention, FIG. 2 is an enlarged plan view of section A in FIG. 1, and FIG. 3 is a longitudinal sectional view of a conventional magnetic disk device. be. l: Magnetic head 2: Arm 3: Holder 4a, 4b: Bearing 5: Central shaft 6: Mass body 7a, 7b, 7c: Leaf spring 8: Mounting with screws 9: Coil 10: Permanent magnet 11: Magnetic circuit 12a, 121
)H housing

Claims (2)

[Claims] (1) having a central shaft rotatably supporting a magnetic disk assembly formed by stacking a plurality of magnetic disks or a magnetic head assembly having a plurality of magnetic heads supported by an arm through a bearing; In a magnetic disk drive in which the central shaft is supported and fixed to the housing by pressing both ends of the central shaft with leaf springs and bringing them into pressure contact with a part of the housing, the leaf spring is connected to the leaf spring. A magnetic disk device characterized in that a metal resonance preventing mass body is bonded with a viscoelastic material interposed therebetween. (2) having a central shaft rotatably supporting a magnetic disk assembly formed by stacking a plurality of magnetic disks or a magnetic head assembly having a plurality of magnetic heads supported by an arm through a bearing; In a magnetic disk drive in which the central shaft is supported and fixed to the housing by pressing both ends of the central shaft with leaf springs and bringing the central shaft into pressure contact with a part of the housing, the leaf spring is attached to the leaf spring. 1. A magnetic disk drive characterized in that a metal resonance-preventing mass body is bonded to the body with a viscoelastic material interposed therebetween, and the stiffness of each leaf spring is made different from each other.