JPH05290535A - Gimbal spring for magnetic disk - Google Patents

Abstract

PURPOSE:To improve the positioning accuracy of a head and to increase a surface recording density by specifying the material quality of the gimbal spring for a magnetic disk. CONSTITUTION:The gimbal spring 3 is constituted of ceramics, fiber reinforced plastic or fiber reinforced metal and its specific elastic modulus is specified to >=30GPa/(Mg/m<3>) or more preferably to >=50GPa/(Mg/m<3>). As a result, the rigidity of the spring 3 is enhanced and the torsion and vibration thereof are suppressed, by which the error in head positioning is lowered to <=0.5mum as compared with 0.9mum of the conventional stainless steel gimbals. The surface recording density is improved to >=17500 track pit/inch<2> as compared with 13000 track pit/inch<2> of the conventional gimbal springs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gimbal spring for a magnetic disk device, which has a head for writing / reading to / from a magnetic disk at its tip and which has a base end attached to a head positioning carriage via a carriage arm, and more particularly to a gimbal spring for a magnetic disk device. The present invention relates to a gimbal spring suitable for improving the positioning accuracy of a head by being made of a ceramics sintered body having high rigidity, fiber reinforced plastic or fiber reinforced metal.

[0002]

2. Description of the Related Art In recent years, with the increase in storage capacity of magnetic disk devices, there is an increasing demand for improvement in the positioning accuracy of the head with respect to the magnetic disk. A conventional rotary type magnetic disk device, as disclosed in JP-A-61-48179 and JP-A-2-149978, has a carriage arm for supporting the base end of a gimbal spring having a head at the end. The carriage rotation shaft portion that supports and rotates the carriage arm is a separate component and has a divided structure. Further, the carriage of the conventional linear type magnetic disk device is made of Al alloy or porous ceramics having a porosity of 20 vol% or more as disclosed in Japanese Patent Laid-Open No. 2-149978.

[0003]

In the above-mentioned prior art, the carriage arm, which is an element constituting the carriage mechanism, and the carriage rotating shaft portion supporting the base end of the carriage arm are made of ceramic so as to have high rigidity. However, no consideration has been given to increasing the rigidity of the gimbal spring attached to extend further from the tip of the carriage arm, and the positioning accuracy of the head is naturally limited. This is because the conventional magnetic disk device uses a metal material for the gimbal spring, and therefore when the carriage rotation shaft is rotated by the motor, the gimbal spring supported at a position away from the rotation shaft is twisted or vibrated. However, there is a problem that an error occurs in the position of the head, which limits the positioning accuracy of the head.

It is an object of the present invention to provide a gimbal spring for a magnetic disk device, which is made of ceramics or fiber reinforced material, which enables a carriage mechanism having a high rigidity which has never been obtained, and which can improve the positioning accuracy of the head. is there.

[0005]

In order to achieve the above object, a gimbal spring for a magnetic disk apparatus according to the present invention has a head for writing / reading to / from a magnetic disk at the tip, and the head at the base end via a carriage arm. A gimbal spring for a magnetic disk device attached to a positioning carriage is characterized in that it is made of a ceramic sintered body, fiber reinforced plastic or fiber reinforced metal.

The ceramic sintered body of the gimbal spring is made of at least one ceramic of carbide, oxide, nitride and oxynitride, and has a porosity of 30 vo.
It is preferably 1% or less, preferably 15 vol% or less. More specifically, the sintered ceramics are ZrO ₂ , mullite, SiC, Si ₂ N ₂ O, Si ₃ N ₄ , AlN, Al ₂ O _3.
And at least one of B ₄ C. Further, the ceramic sintered body preferably has a porosity of 30 vol% or less and a specific elastic modulus of 30 GPa / (Mg / m ³ ) or more.

It is preferable that the gimbal spring of the ceramics sintered body is manufactured through the steps of forming a green sheet of slurry of ceramics powder, punching it into the shape of a gimbal spring, and sintering.

Further, it is preferable to provide a conductive circuit for transmitting an electric signal through the head inside the ceramic sintered body of the gimbal spring.

Further, another gimbal spring for a magnetic disk device of the present invention is made of carbon fiber reinforced plastic or carbon fiber reinforced metal, and the carbon fiber reinforced the base plastic or metal, and through the head. It is characterized in that it also serves as a conductive circuit for transmitting an electric signal.

It is preferable that the fiber-reinforced plastic and the fiber-reinforced metal have a specific elastic modulus of 30 GPa / (Mg / m ³ ) or more.

[0011]

A gimbal spring for a magnetic disk device according to the present invention,
The rigidity can be increased by using a ceramic sintered body, fiber reinforced plastic or fiber reinforced metal, and when the carriage is driven to position the head provided at the tip of the gimbal spring at a predetermined position on the magnetic disk. Further, it is possible to prevent twisting and vibration that occur in the gimbal spring, and it is possible to improve the positioning accuracy of the head.

The reason for setting the porosity of the ceramics sintered body to 30 vol% or less is that if the porosity is larger than that, the rigidity of the gimbal spring decreases, that is, the specific elastic modulus is 30 GPa / (Mg /
m ³ ) cannot be obtained, and the positioning accuracy of the head cannot be sufficiently improved as compared with the conventional case. By the way, stainless steel conventionally used for gimbal springs has a specific elastic modulus.
It is 25 GPa / (Mg / m ³ ).

The gimbal spring has a specific elastic modulus of 30 GPa / (Mg /
When the ceramic sintered body of m ³ ) is used, the positioning accuracy of the head with respect to the magnetic disk can be set to 0.1 μm / inch or less. If this is applied to a 5-inch magnetic disk, the head positioning accuracy can be improved to 0.5 μm or less (Fig. 3), and as a result, the recording areal density of the magnetic disk becomes 16000 track bits / inch ² or more. Can be improved.

A gimbal spring having a specific elastic modulus of 30 GPa / (Mg / m ³ ) can also be obtained by constructing a fiber reinforced plastic or a fiber reinforced metal, and is made of the same magnetic material as the ceramic sintered body. The positioning accuracy of the head with respect to the disk can be set to 0.1 μm / inch or less. In the case of using fiber-reinforced plastic or fiber-reinforced metal, it is possible to use carbon fiber as the fiber to strengthen the plastic or metal, and use the carbon fiber for wiring for transmitting an electric signal to the head.

Thus, by forming the gimbal spring for a magnetic disk with a ceramics sintered body, a fiber reinforced plastic or a fiber reinforced metal, a magnetic disk device excellent in head positioning accuracy can be obtained, and a high recording surface density of the disk can be obtained. Higher processing speed and higher reliability can be achieved.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view schematically showing the configuration of a carriage mechanism of a rotary type magnetic disk device to which a gimbal spring for a magnetic disk device according to an embodiment of the present invention is applied, and FIG.
It is a II-II arrow line view.

In FIG. 1, the carriage mechanism has a gimbal spring 3 provided with a head 2 for writing or reading data on or from a magnetic disk 1 as a recording medium at its tip, and a base end of the gimbal spring 3 is fixed to one end. The carriage arm 4 and a rotary shaft 5 to which the other end of the carriage arm 4 is fixed. When the head 2 is positioned, the magnetic disk 1 rotates in a state where the head 2 is close to the surface of the magnetic disk 1, and the rotary shaft 5 rotates to move the head 2 in a substantially radial direction so as to cross the track of the magnetic disk 1. It is moved and positioned on a predetermined track. At this time, the gimbal spring 3 and the carriage arm 4 are twisted or vibrated, which reduces the positioning accuracy of the head.

In the present invention, the gimbal spring is made of ceramics, fiber reinforced plastic or fiber reinforced metal, so that the gimbal spring is made highly rigid, twisting and vibration of the gimbal spring are suppressed, and the positioning accuracy of the head is improved. .. The advantages of increasing the rigidity of the gimbal spring are 1) the rigidity of the gimbal spring is increased, and the deformation and vibration of the gimbal spring due to the drive of the carriage can be reduced, and 2) the ceramic gimbal used in the head. The difference in coefficient of thermal expansion with the rider can be reduced, and deformation of the gimbal due to sliding heat generated between the ceramic slider and the magnetic disk can be reduced. 3) When the carriage mechanism is made of ceramic, the gimbal spring between the guide arm and gimbal spring can be reduced. The difference in the coefficient of thermal expansion becomes small, and the gimbalno thermal deformation can be made small. Of the above, 1) is the greatest advantage.

FIG. 3 is a diagram showing the relationship between the specific elastic modulus of the gimbal spring and the positioning accuracy of the head. By increasing the specific elastic modulus of the gimbal spring, that is, increasing the rigidity,
It is shown that the head positioning accuracy can be improved to more than double the conventional level. This accuracy is obtained by simulation calculation for a 5-inch magnetic disk, and the smaller the disk diameter, the higher the positioning accuracy.

In FIG. 3, the conventional stainless steel gimbal spring has a specific elastic modulus of 25 GPa / (Mg / m ³ ) and a head positioning accuracy of 0.9 μm. On the other hand, the gimbal spring is made of ceramics, fiber reinforced plastic, or fiber reinforced metal and has a specific elastic modulus of 30 GPa / (Mg / m ³ ).
By the above, the head positioning accuracy ratio to the disk diameter is 0.1 μm / inch or less, that is, the head positioning accuracy is 0.5 μm in the case of a 5-inch disk.
It can be improved to the following. As a result, the recording areal density of the disk can be improved to 16000 track bits / inch ² or more. In the figure, the curve A in the white plot shows the head positioning accuracy when only the gimbal spring is made highly rigid. Further, by making the gimbal spring having the head highly rigid as described above, and by making the carriage mechanism portion supporting the gimbal spring a ceramic sintered body, the head positioning accuracy ratio to the disk diameter is 0.05 μm / inch or less, that is, In a 5-inch disk, the head positioning accuracy can be improved to 0.25 μm or less. As a result, the density of the disc can be further increased. As a result, the recording surface density of the disk can be improved to 20000 track bits / inch ² or more. In the figure, the curve B of the black plot shows the head positioning accuracy when the gimbal spring and the carriage mechanism section are made highly rigid.

When the high-rigidity gimbal spring is made of a ceramic sintered body, the porosity of the sintered body should be 30 vol% or less, preferably 15 vol% or less. Ceramic materials include ZrO ₂ , mullite, SiC, Si ₂ N ₂
O, Si ₃ N ₄ , AlN, Al ₂ O ₃ , B ₄ C, or a mixture of two or more thereof is used. Furthermore, it is even better to use ceramics having higher rigidity than that of a simple substance by being compounded, fiber reinforced, and particle dispersion strengthened. The porosity of the sintered body should be 30 vol% or less, preferably 15 vol% or less. If the porosity exceeds 30 vol%, the specific elastic modulus of the sintered body decreases, which is required for a high-rigidity gimbal spring. A specific elastic modulus of 30 GPa / (Mg / m ³ ) cannot be obtained.

As the method for producing the sintered body, normal pressure sintering, reaction sintering, hot pressing (HP), hot isostatic pressing (HIP), etc. can be used. Particularly, atmospheric pressure sintering and reaction sintering are effective in terms of cost. These manufacturing methods can be similarly applied to the case where the carriage mechanism portion other than the gimbal spring is made of ceramics. As a manufacturing method of the gimbal spring, the green sheet molding method is advantageous for the low cost manufacturing method. This is a method of forming a green sheet with a doctor blade using a slurry composed of an organic binder and ceramic powder, cutting it into an arbitrary shape by punching, and sintering. The suitable thickness of the green sheet is 50 μm to 3 mm.
If necessary, wiring such as copper is printed to form a conductive circuit to the head at the tip. It is also possible to stack green sheets. After punching, the ends may be bent if necessary, or after sintering, finishing may be performed if necessary. Considering the electric signal speed of the conductive circuit, the permittivity should be as small as possible. Mullite and AlN are preferred because of their low dielectric constant.

Further, in bonding the gimbal spring of the ceramic sintered body and the carriage mechanism part, it is important that the stress acting on the bonding part is set to not more than the shear strength of the adhesive,
It is also possible to combine the adhesive and mechanical joining, and it is also possible to integrally sinter with the carriage arm of the ceramic sintered body.

For the high-rigidity gimbal spring, in addition to ceramics, it is effective to use fiber-reinforced plastic or fiber-reinforced metal in which fibers or particles of ceramics or carbon are dispersed in plastic or metal to increase rigidity. is there.
Fiber-reinforced metal in which ceramic (SiC) particles or ceramic (SiC) fibers are dispersed in Al has a specific elastic modulus of 50 GPa / (Mg /
m ³ ) or more, which is very effective. Further, the fiber reinforced plastic in which carbon fiber is dispersed in epoxy has a large specific elastic modulus of 80 GPa / (Mg / m ³ ) or more and is very effective.
It is also possible to use carbon fibers oriented in plastic for wiring for transmitting electric signals between heads.

FIG. 4 shows an example of the structure of a gimbal spring, which has a stepped structure to have a spring action in the plate thickness direction in addition to increasing the plate thickness to increase the torsional rigidity. Further, as shown in FIG. 5, a combined structure in which the stainless steel piece 6 and the ceramic piece 7 are connected to each other so as to cause a spring action is also possible. 4 and 5, (a) is a side view and (b) is a plan view. Hereinafter, a method for manufacturing a high-rigidity gimbal spring will be described in detail.

[Examples 1 to 8] As a ceramic raw material for gimbal springs, ZrO ₂ powder having an average particle size of 1 μm: 95
Parts by weight, Y ₂ O ₃ powder having an average particle size of 0.5 μm: 5 parts by weight, polyvinyl butyral: 6 parts by weight, trichloroethylene: 24 parts by weight, tetrachloroethylene: 32 parts by weight, n-butyl alcohol: 44 Binder consisting of 1 part by weight and 2 parts by weight butyl phthalyl glyco-butylate:
108 parts by weight were added and mixed with a ball mill for 24 hours to prepare a slurry.

The slurry was vacuum degassed to remove air bubbles, then formed on a polyester film with a doctor blade to a thickness of 0.1 mm, and dried in an argon atmosphere furnace at 100 ° C. for 10 hours. Then, a green sheet was prepared.

The green sheet is cut into a 100 mm square, and a through hole is formed at a required position, and then the through hole is formed.
Conductor circuits were formed by a printing method using a paste based on tungsten in the wiring pattern and a predetermined wiring pattern portion. The surfaces on which the conductor circuits are formed are aligned and the green
Hot-pressed (150 ℃, 1 hour)
Then, it was pressure-bonded and cut into a gimbal spring shape to obtain a green molded body.

Then, the green compact was heated to 1700 ° C. at a heating rate of 10 ° C./h in a furnace in an argon gas atmosphere, and left to cool in the furnace to obtain a sintered body. The binder and the like are degreased during the temperature rising process. Thus, a ceramic gimbal spring having internal wiring and a sintered body having a porosity of 3 vol% and a specific elastic modulus of 35 GPa / (Mg / m ³ ) was obtained. This ceramic gimbal spring 3 was adhered to an Al carriage arm. For comparison, a case of a stainless steel gimbal spring and an Al carriage arm was also examined.

[0030]

[Table 1]

As shown in Table 1, as compared with the conventional stainless steel gimbal spring of Comparative Example 1, ZrO _{2 of} Example 1 was compared.
Since the specific elastic modulus of the gimbal spring made of a sintered body is approximately doubled, the head positioning error caused by the twist mode of the gimbal spring can be reduced to 0.5 μm or less,
As a result, the recording surface density of the disc could be increased to 17,000 track bits / inch ² or more. Further, as shown in the second embodiment, as a result of making the carriage arm 2 ceramic like the gimbal spring, the head positioning error is 0.3 μm.
It is possible to reduce the recording surface density of the disc to 20 or less.
We were able to achieve over 000 track bits / inch ² .
On the other hand, in the case of a stainless steel gimbal spring and an Al carriage arm, the head positioning accuracy is as large as 0.9 μm or more, and the recording surface density of the disk is 13000
It can be seen that it is as small as a track bit / inch ² or less.

[0032]

[Table 2]

Table 2 shows that, in place of the ceramic raw material ZrO ₂ used in Examples 1 and 2, AlN, SiC, Si ₃ N ₄ , Al.
₂ shows specific elastic modulus, head positioning accuracy, and disk recording areal density in Examples 3 to 8 manufactured using ₂ O ₃ , mullite, and Si ₂ N ₂ O, respectively. Examples 3 and 5-8
Is a combination of a ceramic gimbal spring and an Al carriage arm.
The carriage arm is made of ceramic,
The positioning accuracy of the head can be improved by using the gimbal spring made of the above various ceramics. Further, various ceramics can be appropriately mixed and used. Fabrication by the green sheet molding method as in this embodiment is extremely advantageous in terms of cost.

The method of molding ceramics includes gimbal springs such as die powder molding, CIP, injection molding and casting molding,
Any method may be used as long as the shape of the carriage arm can be formed.

The molding binder such as the green sheet is generally used as a binder for molding ceramics such as polymer materials such as polyvinyl butyral and polyethylene, silicone compounds and polysilane compounds. Things can be used. The method of degreasing these binders is not particularly limited, but degreasing can be performed by controlling the temperature rising rate during sintering.

Specific examples of the metal forming the conductive circuit include tungsten, molybdenum, chromium, manganese,
There are alloys containing iron, cobalt, nickel, iridium or one of these elements as a main component, and they can be used according to the purpose. The conductive circuit is formed by adding a binder to these metals to form a paste, and then applying the pattern to a molded product such as a green sheet, forming a pattern by a method such as printing, and sintering the molded product. Is formed by

In the above embodiments, the gimbal spring used in the rotary type magnetic disk device has been described.
It has been confirmed that a ceramicized gimbal spring is similarly effective in the case of a linear memory device.

[Embodiment 9] The ceramic gimbal spring of this embodiment is formed by an injection molding machine. A mixture of 95 parts by weight of Si ₃ N _{4 having} an average particle size of 0.2 μm powder, ₃ parts by weight of Y ₂ O _{3 as} a sintering aid, ₂ parts by weight of Al ₂ O ₃ and polyethylene, and stearic acid and a synthetic wax. : 13
It was kneaded with 1 part by weight to obtain a raw material. A gimbal spring having a thickness of 0.8 mm was produced from this raw material using an injection molding machine. After removing the wax content in the molded body, it was heat-treated in nitrogen gas at 1700 ° C. for 5 hours. The specific elastic modulus (Young's modulus / density) of this ceramic gimbal spring is 90 GPa / (Mg / m ³ ), which is more than three times larger than that of stainless steel, and the head positioning error can be reduced to 0.3 μm or less. The recording areal density of the disk was able to reach 20000 track bits / inch ² or more.

In this embodiment, instead of Si ₃ N ₄ ,
SiC, Si ₂ N ₂ O, AlN, Al ₂ O ₃ , ZrO ₂ , B ₄ C,
Even if BN or mullite is used, the positioning accuracy of the head can be similarly improved. Further, composite ceramics such as SiC / Si ₃ N ₄ may be used. It is also possible to combine with whiskers and fibers.

In the ceramic gimbal spring of the present invention, the porosity of the ceramic sintered body is preferably 30 vol% or less because the Young's modulus decreases as the porosity increases, and the specific elastic modulus (Young's modulus / density) increases. Because it cannot be improved. From the relationship between the specific elastic modulus (Young's modulus / density) of the gimbal spring and the positioning accuracy of the head shown by the curve A in FIG. 3, in order to reduce the positioning error of the head, the specific elastic modulus of the gimbal spring (Young's modulus / density) 30 GPa / (Mg /
m ³ ) or more, preferably 50 GPa / (Mg
/ m ³ ) or more is recommended. Further, as shown by the curve B in FIG. 3, if both the gimbal spring and the carriage arm are made of ceramics, the positioning accuracy can be greatly improved.

[Embodiment 10] The gimbal spring of this embodiment is provided with a conductive circuit formed of a carbon fiber bundle inside. As a ceramic raw material for gimbal springs, 95 parts by weight of AlN powder having an average particle size of 1 μm, 5 parts by weight of Y ₂ O ₃ powder having an average particle size of 0.5 μm, polyvinyl butyral: 6 parts by weight, trichloroethylene: 24 parts by weight, tetrachloroethylene: 32 parts by weight, n-butyl alcohol: 44 parts by weight and butylphthalylglycolate-butylate: 2 parts by weight: 108 parts by weight of a binder are added together, and a ball mill is used for 24 hours. The mixture was mixed into a slurry.

The slurry is vacuum degassed to remove air bubbles,
Then, a doctor blade was used to form a film having a thickness of 0.1 mm on the polyester film, and the film was formed in an argon atmosphere furnace at 10
It was dried at 0 ° C for 10 hours to prepare a green sheet.

The green sheet was cut into 100 mm square, and a predetermined wiring pattern was formed on the surface of the green sheet by using a carbon fiber bundle having a diameter of 0.1 mm. This is green
In the sheet, scissors are laminated in three layers and then hot pressed (15
It was pressed at 0 ° C. for 1 hour) and cut into a gimbal spring shape to obtain a green molded body. The green compact was heated to 1850 ° C. at a temperature rising rate of 10 ° C./h in a nitrogen atmosphere furnace, and allowed to cool in the furnace to obtain a sintered body. This sintered body had a porosity of 2 vol% and a specific elastic modulus of 90 GPa / (Mg / m ³ ). The binder and the like are degreased during the temperature rising process.

As described above, the ceramic gimbal spring having the carbon internal wiring has a specific elastic modulus improved to about 4 times that of the conventional stainless steel gimbal spring. Therefore, the head positioning caused by the twist mode of the gimbal spring is positioned. The error can be reduced to less than 0.3 μm, and as a result, the recording areal density of the disc is increased to 20000 track bits / in.
I was able to make ch ² or higher.

It has been confirmed that the gimbal spring of this embodiment has the same effect when applied to a linear type magnetic disk device.

[Embodiment 11] This embodiment is a gimbal spring made of fiber reinforced plastic. As a fiber reinforced plastic raw material for gimbal springs, an epoxy resin is used, the epoxy resin slurry is vacuum deaerated to remove air bubbles, and then a doctor blade is used to form a 1 mm thick film on the polyester film, 5 in an argon atmosphere furnace
It was dried at 0 ° C. for 24 hours to prepare a green sheet.

This green sheet was cut into 100 mm square, and a predetermined wiring pattern was formed on the surface of the green sheet by using a carbon fiber bundle having a diameter of 0.3 mm. This is green
After laminating two layers of scissors, hot press (200
Crimping was carried out for 1 hour (° C, 1 hour), and cut into a gimbal spring shape. As a result, a material having a specific elastic modulus of 85 GPa / (Mg / m ³ ) was obtained.

The gimbal spring made of fiber reinforced plastic having the carbon internal wiring thus obtained is
Since the specific elastic modulus is improved about 4 times as compared with the conventional stainless steel gimbal spring, the head positioning error caused by the torsion mode of the gimbal spring can be reduced to 0.3 μm or less, and as a result, the disc The recording areal density could reach 20000 track bits / inch ² or more.

It has been confirmed that the gimbal spring of this embodiment has the same effect when applied to a linear type magnetic disk device.

[Embodiment 12] This embodiment is a gimbal spring made of fiber reinforced metal. As the fiber-reinforced metal for the gimbal spring, 20 vol% of SiC fiber (diameter 3 μm, aspect ratio 40) was dispersed and Al was used. Specific elastic modulus 45
The one with GPa / (Mg / m ³ ) was obtained, and the relative elastic modulus was improved to about 2 times compared with the conventional stainless steel gimbal spring, so the head positioning error caused by the torsion mode of the gimbal spring was The recording surface density of the disc can be reduced to 0.5 μm or less.
Bit / inch ² or more could be achieved. The shape of the gimbal spring can be manufactured by a usual method such as forging and pressing.

[0051]

According to the present invention, since the gimbal spring is made of ceramic, fiber reinforced plastic or fiber reinforced metal, the rigidity of the gimbal spring can be increased, and twisting and vibration of the gimbal spring that occur during movement for head positioning can be achieved. It is possible to suppress, head positioning accuracy is extremely excellent, and thus high areal density recording is possible, and reliability and speeding up of the magnetic disk device actuator and the optical disk device actuator can be significantly improved.

[Brief description of drawings]

FIG. 1 is a plan view schematically showing a configuration of a magnetic disk device carriage.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a diagram showing the relationship between the specific elastic modulus of the gimbal spring and the positioning accuracy of the head.

FIG. 4 is a diagram showing a structural example of a gimbal spring according to the present invention.

FIG. 5 is a view showing another structural example of the gimbal spring according to the present invention.

[Explanation of symbols]

 1 magnetic disk 2 head 3 gimbal spring 4 carriage arm 5 rotating shaft 6 stainless steel piece 7 ceramic piece

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Nishimura 2880 Kozu, Odawara City, Kanagawa Stock Company Hitachi Ltd. Odawara Factory

Claims (9)

[Claims] 1. A gimbal spring for a magnetic disk device, which has a head for writing and reading on a magnetic disk at a tip thereof and a base end of which is attached to a head positioning carriage via a carriage arm, wherein a ceramic sintered body, fiber reinforced plastic or A gimbal spring for a magnetic disk device, which is made of any one of fiber-reinforced metals. 2. A gimbal spring for a magnetic disk device having a head for writing / reading to / from a magnetic disk at the tip and having a base end attached to a head positioning carriage via a carriage arm, the gimbal spring comprising a ceramic sintered body, A gimbal spring for a magnetic disk device, wherein a conductive circuit for transmitting an electric signal through the head is provided in a ceramic sintered body. 3. A gimbal spring for a magnetic disk device, which has a head for writing and reading on a magnetic disk at its tip and whose base end is attached to a head positioning carriage via a carriage arm, wherein carbon fiber reinforced plastic or carbon fiber reinforced metal is used. And a conductive circuit for transmitting an electric signal through the head is formed by the carbon fiber. 4. The ceramic sintered body is made of at least one of carbide, oxide, nitride and oxynitride, and has a specific elastic modulus of 30 GPa / (Mg / m ³ ) or more with a porosity of 30 vol% or less. The gimbal spring for a magnetic disk device according to claim 1 or 2, characterized in that it has. 5. The ceramics sintered body is ZrO ₂ , S
The gimbal for a magnetic disk drive according to claim 1 or 2, which is composed of at least one of iC, mullite, Si ₃ N ₄ , AlN, Al ₂ O ₃ , B ₄ C and Si ₂ N ₂ O. Spring. 6. The ceramics sintered body is manufactured through a green sheet forming process of a slurry of ceramic powder, punching into a predetermined shape, and sintering. A gimbal spring for a magnetic disk device according to any one of 4, 4 and 5. 7. The fiber reinforced plastic has a specific elastic modulus of 30.
The gimbal spring for a magnetic disk device according to claim 1 or 3, wherein the gimbal spring is configured to have GPa / (Mg / m ³ ) or more. 8. The fiber reinforced metal has a specific elastic modulus of 30 GPa /
The gimbal spring for a magnetic disk device according to claim 1 or 3, wherein the gimbal spring is configured to have (Mg / m ³ ) or more. 9. A magnetic disk device comprising the gimbal spring for a magnetic disk device according to claim 1.