JPH05159485A - Storage device - Google Patents

Abstract

PURPOSE:To improve the positioning accuracy of a head by constituting a carriage of specific ceramics having a high specific modulus of elasticity. CONSTITUTION:The carriage supporting a head is constituted of the sintered body of specific ceramics having <=15vol.% porosity and >=60GPa/(Mg/m<3>) specific modulus of elasticity. The carriage which is small in the size change rate at the time of sintering from a molding to the sintered body and has the high dimensional accuracy is obtd. and the positioning accuracy of the head generated a reciprocating mode is decreased to <=0.3mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a readable / writable linear carriage mechanism for a storage device, and more particularly to a storage device having a head with a high specific modulus ceramics carriage mechanism and excellent positioning accuracy.

[0002]

2. Description of the Related Art In recent years, in magnetic disk devices, the demand for head positioning accuracy has increased as storage capacity has increased. The carriage of the conventional linear 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]

The above-mentioned prior art does not take into consideration the positioning accuracy of the head as the density of the disk increases, and the conventional technology configuration has a limit in the positioning accuracy of the head. It was not possible to cope with high density.

The object of the present invention is to make a carriage mechanism (including an arm) of ceramics having a high specific elastic modulus, which enables a carriage mechanism having a high rigidity which has never been achieved.
An object of the present invention is to provide a storage device having excellent head positioning accuracy.

[0005]

The above object can be achieved by forming a carriage for supporting a head by a high specific modulus ceramics sintered body in a storage device. As shown in FIG. 1, a method of molding and sintering the entire carriage that supports the head. 1. A method in which a single carriage arm and a main body of the carriage shown in FIG. This stack can be sintered, metallized, organic bonded, etc.

Thus, by using a ceramic sintered body for the carriage that supports the head, the ratio of the disk diameter to the head positioning accuracy can be improved to 0.06 μm / inch or less. For example, with a 5-inch disk, the head positioning accuracy can be improved to 0.3 μm or less.

According to the present invention, the carriage has a porosity of 15 vol.
% Or more of at least one kind of ceramics of carbide, oxide, nitride and oxynitride. The ceramic carriage is made of Si ₂ N ₂ O, Si ₃ N ₄ ,
AlN, Al ₂ O ₃ , ZrO ₂ , B ₄ C, BN, consisting of ceramics of a composition containing at least one of mullite,
The specific resistance is 2 × 10 ⁴ Ωm or more, preferably 10 ⁷ Ωm or more. By increasing this specific resistance as much as possible, the eddy current generated from the coil can be prevented. In the manufacturing method of the present invention, pressureless sintering, reaction sintering, HP, HIP, etc. can be used. Particularly, reactive sintering is effective from the viewpoint of cost.

In the present invention, the carriage is made of carbide, oxide,
At least one inorganic compound of nitride or oxynitride 40v
By using ceramics having a porosity of 15 vol% or less with a composition of 1 vol% or less and Si ₃ N ₄ 60 vol% or more,
Since Si ₃ N ₄ has a large specific resistance, a carriage having a specific resistance of 10 ⁷ Ωm or more can be easily manufactured. Here, the inorganic compound is Si ₂ N ₂ O, Si ₃ N ₄ , SiC, TiN, Ti.
C, Al ₂ O ₃ , AlN, ZrN, ZrC, ZrO ₂ or the like can be used.

According to the present invention, the carriage is composed of at least one inorganic compound of oxide, nitride and oxynitride and metal Si.
By forming a ceramic having a porosity of 18 vol% or less, which is obtained by nitriding a compact made of powder and is bonded with Si ₃ N ₄ , the dimensional change rate at the time of sintering from the compact to the sintered compact is small, It is possible to obtain a carriage with high dimensional accuracy.
In the present invention, the porosity of the ceramic carriage is 15 vol.
% Or less, preferably 10 vol% or less. The reason is that if the porosity is more than 15 vol%, the Young's modulus is lowered, which is not preferable. In order to set the head positioning accuracy to 0.06 μm / inch or less, it is necessary to set the specific elastic modulus of the ceramic carriage to 60 GPa / (Mg / m ³ ) or more.

In bonding the ceramic carriage and the gimbal, it is important that the stress acting on the bonded portion is not more than the shear strength of the adhesive, and it is possible to combine the adhesive and mechanical bonding.

[0011]

The present invention relates to a storage device, and by constructing the carriage with ceramics having a high specific elastic modulus, a storage device having excellent head positioning accuracy can be obtained.
Higher processing speed and higher reliability can be achieved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below by taking a 5-inch magnetic disk device as an example.

Example 1 Metal S having an average particle size of 0.9 μm
80 parts by weight of i powder and 20 parts by weight of SiC powder having an average particle size of 5 μm were mixed with methanol in a pot mill and dried, and then 10 parts by weight of polyethylene wax was added to obtain 1
Kneading was carried out at 50 ° C. for 5 hours using a pressure kneader. Then, the mixture was pulverized and molded into a carriage shape 1 in FIG. 1 by an extrusion molding method. After removing the wax content of the molded body, it was heat-treated in nitrogen gas stepwise at a temperature of 1380 ° C. over a long period of time to obtain a Si ₃ N ₄ -bonded SiC ceramics. At this time, the dimensional change rate from the molded body to the sintered body was as small as 0.1%, and the one having excellent dimensional accuracy was obtained. The porosity of the sintered body is 15
%Met. A gimbal 3 with a head 2 was adhered to the carriage 1.

For comparison, a case of an Al carriage and a case of a porous ceramic carriage were also examined.

As shown in Table 1, since the specific elastic modulus is improved about three times as compared with the conventional Al carriage, the positioning accuracy of the head generated by the reciprocating motion mode is less than 0.3.
It could be reduced to 3 μm or less.

[0016]

[Table 1]

On the other hand, when the carriage is made of Al, the positioning accuracy of the head is 1.50 μm, and when it is made of a porous ceramic carriage, the positioning accuracy of the head is good.
You can see that it is as large as 0.54 m.

Carriage having different porosities was manufactured using the materials of this example, and the relationship between porosity and head positioning accuracy was investigated. The result is shown in FIG. From this, in this example, instead of the SiC particles, Si ₃ N ₄ and Si _{2 were used.}
N ₂ O, TiN, TiC, AlN, Al ₂ O ₃ , ZrN, Z
Specific modulus (Young's modulus / density) even when rC and ZrO ₂ are used
By setting the ratio to 60 GPa / (g / m ³ ) or more, the positioning accuracy of the head can be similarly improved. By producing the reaction sintered material as in this example, there is almost no dimensional change from the molded body to the sintered body, so that a member with high dimensional accuracy can be obtained, which is extremely advantageous in terms of cost. ..

There is no problem in terms of characteristics even if the pores of the present ceramic are impregnated with plastic, glass or the like.

Molding of ceramics is performed by mold powder molding, C
Any shape such as IP, injection molding, and cast molding is possible as long as the shape of the present invention is possible.

Example 2 Si _{3 having an} average particle size of 0.2 μm
N ₄ powder 95 parts by weight, sintering aid Y ₂ O ₃ 3 parts by weight, Al ₂ O
₃ 2 parts by weight mixture of 13 parts by weight addition of a synthetic wax polyethylene and stearic acid, was kneaded material. A carriage molded body was produced from this raw material by using an injection molding machine. After removing the wax content in the molded body, in nitrogen gas,
Heat treatment was performed at 1700 ° C. for 5 hours to obtain ceramics having a porosity of 1%.

The specific elastic modulus (Young's modulus /
Density) is 90 GPa / (g / m ³ ), which is three times larger than that of Al alloy, and head positioning error is 0.2 μm.
It was possible to reduce to the following.

In this embodiment, instead of Si ₃ N ₄ ,
SiC, Si ₂ N ₂ O, AlN, Al ₂ O ₃ , ZrO ₂ , B ₄
Even if C, BN, or mullite is used, the positioning accuracy of the head can be similarly improved. However, SiC alone is not preferable because of its low volume resistivity. Therefore, SiC
Composite ceramics such as / Si ₃ N ₃ may be used. It is also possible to combine with whiskers and fibers.

In the present invention, the porosity of the ceramic is 15v.
It is preferable to set it to be not more than ol%, because if the porosity increases, the Young's modulus decreases and the specific elastic modulus (Young's modulus / density) cannot be improved. FIG. 2 shows the relationship between the specific elastic modulus and the positioning accuracy of the head by changing the specific elastic modulus (Young's modulus / density) of the carriage of this embodiment. From this, the specific modulus is to reduce the positioning accuracy of the head (Young's modulus / density) of 60 GPa / (Mg / m ³⁾ or more, preferably requires there to be 80 GPa / (Mg / m ³⁾ or more.

Example 3 SiC with an average particle size of 0.2 μm
AlN powder 17 having 78 parts by weight of powder and an average particle size of 0.2 μm
25 g of distilled water was added to 100 g of a raw material prepared by mixing 0.5 part by weight of sodium metaphosphate and 0.5 part by weight of citric acid with ₃ parts by weight of B ₄ C and ₂ parts by weight of Y ₂ O _{3 as a} sintering aid, and using a pot mill. It was mixed for 24 hours and used as a raw material. A carriage molded body was produced from this raw material by a casting method. After removing water and wax from the molded product, in nitrogen gas at 1700 ° C
And heat-treated for 5 hours to obtain ceramics having a porosity of 1%.

The specific modulus of elasticity of this ceramic (Young's modulus /
Density) is 120 GPa / (g / m ³ ), which is three times larger than that of SUS, and the head positioning error is 0.15 μm.
It was possible to reduce to the following.

The present invention is applicable not only to 5 inches.
In particular, the larger the disc, the greater the effect.

[0028]

According to the present invention, the head positioning accuracy can be made excellent.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a carriage for a storage device.

FIG. 2 is a characteristic diagram showing a relationship between porosity of a carriage and positioning accuracy of a head.

[Explanation of symbols]

1 ... Carriage, 2 ... Head, 3 ... Gimbal, 4 ... Guide rail, 5 ... Rail housing, 6 ... Magnetic disk,
7 ... Bearing, 8 ... Spindle, 9 ... Coil, 10 ...
Permanent magnet, 11 ... Spacer.

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

Claims (8)

[Claims] 1. A carriage for supporting a head has a porosity of 15
vol% or less, the specific modulus 60GPa / (Mg / m ³⁾ or more carbides, oxides, nitrides, storage apparatus characterized by constituting the ceramic sintered body comprising at least one oxynitride. 2. A carriage for supporting a head is provided with a porosity of 15
vol% or less, volume resistivity of 2 × 10 ⁴ Ωm or more, and specific elastic modulus of 60 GPa / (Mg / m ³ ) or more of a ceramic sintered body made of at least one of carbide, oxide, nitride, and oxynitride A storage device characterized by the above. 3. A carriage is formed of a ceramics sintered body made of at least one kind of carbide, oxide, nitride and oxynitride having a porosity of 15 vol% or less and a specific elastic modulus of 60 GPa / (Mg / m ³ ) or more, A storage device characterized in that the ratio of the disk diameter to the head positioning accuracy is 0.06 μm / inch or less. 4. A carriage having a porosity of 15 vol% or less, a volume resistivity of 2 × 10 ⁴ Ωm or more, and a specific elastic modulus of 60 GPa /
(Mg / m ³ ) or more, formed of a ceramics sintered body made of at least one kind of carbide, oxide, nitride, and oxynitride, and the ratio of disk diameter to head positioning accuracy is 0.06 μm / inch or less. A storage device characterized by. 5. The ceramic sintered body according to claim 1, 2, 3, or 4, wherein Si ₂ N ₂ O, Si ₃ N ₄ , AlN,
A memory device having a structure containing at least one of Al ₂ O ₃ , B ₄ C, BN, and mullite. 6. The carriage according to claim 1, 2, 3 or 4, wherein the carriage comprises Si ₃ N ₄ and 40% by volume or less of at least one inorganic compound of carbide, oxide, nitride and oxynitride.
A storage device made of ceramics having a composition of 60 vol% or more and a porosity of 15 vol% or less. 7. The Si according to claim 1, 2, 3 or 4, wherein the carriage is obtained by nitriding a compact made of at least one inorganic compound of oxide, nitride and oxynitride and metal Si powder. Ceramics in which the inorganic compound is bonded with ₃ N ₄ , and the porosity in the ceramics is 15 vol%
Hereinafter, a storage device having a Si ₃ N ₄ content of 60 vol% or more. 8. The inorganic compound according to claim 6 or 7, wherein the inorganic compound is Si ₂ N ₂ O, Si ₃ N ₄ , SiC, TiN, TiC,
A memory device comprising at least one of AlN, Al ₂ O ₃ , ZrN, and ZrC.