JPH11297019A - Manufacture of glass spacer for media - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for the glass spacer for media which is hard to chop at its corner part. SOLUTION: The glass spacer 26 has a ring-shaped outward appearance and is fitted onto a rotary column body 14 and interposed between media 22 loaded on the rotary column body 14 to form a specific gap between the media 22. This manufacturing method includes a process for forming a ring body 27 by using glass, a process for arcuately sectioning the corner parts C of the ring body 27 along a radius over the entire circumference through metal mold molding while the corner parts C of the ring body 27 are directly heated and fused or while the whole ring body 27 is softened, and a process for grinding and flattening both the end surfaces of the ring body 27 except the arcuate parts of the corner parts C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a glass spacer for a medium, which is mounted together with a plurality of media on a rotating column provided in a hard disk drive.

[0002]

2. Description of the Related Art A plurality of media (referred to as magnetic disk media having a magnetic layer for storing data on the surface) of a hard disk drive are mounted together with a glass spacer for media (also simply referred to as a spacer). The structure of the rotating column will be described with reference to FIG. 10
Reference numeral denotes an electric motor, and the outer shape of the hard disk device is fixed to a part of a chassis 12 formed in a box shape. 1
Reference numeral 4 denotes a rotating column attached to the rotating shaft 16 of the electric motor 10. A flange portion 18 is formed at an end (lower end) of the rotating column 14 on the chassis 12 side. In addition, a female screw hole 20 is provided on the upper surface of the rotating column 14.

Reference numeral 22 denotes a medium which is formed in a thin disk shape using a glass material. A mounting hole 24 having a diameter slightly larger than the outer diameter of the rotary column
The rotary column 14 is inserted into the mounting hole 24, and is mounted on the rotary column 14 in a state where the rotary column 14 is externally fitted to the rotary column 14. The medium 22 has a magnetic layer (not shown) formed by coating a magnetic material on both end surfaces (upper and lower surfaces in FIG. 1).
Data recording is performed, and the recorded data is read out.

Reference numeral 26 denotes a spacer. This spacer 26
2 and 3 are formed in a ring shape that can be externally fitted to the rotating column 14, and are provided on the rotating column 14 together with the plurality of media 22, between the media 22, and between the media 22 and a clamp described later. The medium 22 is provided with a predetermined interval (for example, 1.5 to 2.0 mm) between the media 22. The spacer 26 is
As an example, a ring body formed by cutting a glass tube into a predetermined thickness, and flattening by grinding and polishing both end surfaces thereof, and a grinding process for making both end surfaces parallel to each other,
It is manufactured by performing a roughening process for roughening both end surfaces and a cleaning process. The inner diameter of the spacer 26 is formed slightly larger than the outer diameter of the rotating column 14, and the outer diameter is formed to be substantially the same as the outer diameter of the flange portion 18 of the rotating column 14. 28
Is a clamp, which is a member for fixing the medium 22 to the rotating column 14. This clamp 28 is shown in FIGS.
Is formed in a thin disk shape having substantially the same outer diameter as the spacer 26, and a through hole 30 is provided in a central portion thereof,
A concave groove 32 is provided around the outer edge along the circumferential direction.

[0005] Then, as shown in FIG.
After the plurality of media 22 and the spacers 26 are externally fitted in a state of being alternately stacked on the rotating column 14, they are fixed to the upper surface of the rotating column 14 using a male screw 34. At this time, the lower end of the concave groove 32 presses the spacer 26 disposed at the uppermost position downward, so that the plurality of media 22 and the spacer 26 are sandwiched between the clamp 28 and the flange portion 18 and Will be fixed. When the clamp 28 is screwed by the male screw 34, the central portion is dented and elastically deformed, and the elastic force of the elastic deformation presses the spacer 26 abutting the concave groove 32 downward.

Conventionally, the spacer 26 and the clamp 28 have been formed using a metal material. However, in recent years, the medium itself may be manufactured using glass. In such a case, the medium is closely adhered to the medium. If the coefficient of thermal expansion between the spacer and the spacer is different, the stress acts on the medium due to the temperature change and the medium is distorted.
In order to avoid such a problem that an error occurs at the time of data recording or reading by the method 5 and the reliability of the hard disk device is reduced, the spacer itself is also made of glass and the thermal expansion coefficient of the medium 22 is made uniform. It has become.

[0007]

However, the above-mentioned conventional glass spacer has the following problems. When the spacer 26 is manufactured, both end faces of the ring body that are in contact with the media 22 and the clamp 28 need to be flattened, and the end faces are ground and polished. Since the ring body 27 is formed by cutting a glass tube into a circle, the cross-sectional shape along the radial direction is rectangular or square as shown in FIG. Therefore, the four corners of the cross section, that is, both end surfaces 27a and the inner peripheral surface 27b which are sequentially ground, and both end surfaces 27a and the outer peripheral surface 27c
Since the joining portion (corner portion) C is always substantially at a right angle, there is a problem that it is easily chipped during grinding or polishing. Even if the corner portion is not chipped in the grinding / polishing process, the cross-sectional shape along the radial direction of the manufactured spacer 26 has four right angles and the tip is sharp, so that the material may be glass. Yes, spacer 2
6, when it comes into contact with other members when it is mounted on the rotary column 14, or when it is pressed by the clamp 28 after being mounted on the rotary column 14, There is a problem that C is easily missing.

Therefore, in the related art, there is a case where the corner portion C is further subjected to a polishing process to perform chamfering to eliminate a sharp portion. However, since the tip of the corner portion C is originally sharp as described above, this polishing process is performed. There is also a problem that the corner C is easily chipped.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method for manufacturing a glass spacer for a medium, which has a corner portion which is not easily chipped.

[0010]

The present invention has the following arrangement to achieve the above object. That is, a glass for media having a ring-shaped outer shape, being interposed between a plurality of media fitted to the rotating column and fitted to the rotating column, and forming a predetermined gap between the media. In the method of manufacturing a spacer, a step of forming a ring body using glass, and directly heating and melting a corner portion of the ring body, or performing die molding in a state where the entire ring body is softened, Forming a circular cross-sectional shape along the radial direction over the entire circumference, and grinding and flattening both end faces of the ring body while leaving the arc-shaped portion of the corner portion. It is characterized by the following. According to this configuration, the cross-sectional shape along the radial direction of each corner portion of the glass spacer is formed in an arc shape from the original right-angled shape by heat melting or molding over the entire circumference. Therefore, even if the corner portion receives an impact force due to contact with another member or the like, the corner portion is less likely to be chipped as compared with a state in which the corner portion remains in a right angle shape.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method for manufacturing a glass spacer for media according to the present invention will be described below in detail with reference to the accompanying drawings. The same components as those described in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. (First Embodiment) First, a glass ring body 27
Is formed (manufactured) (ring body forming step). By subjecting the ring body 27 to a grinding process, a polishing process, a surface roughening process, and, in some cases, a film forming process, a spacer 26 having a predetermined thickness and a predetermined surface roughness is finally obtained. . Since the ring body 27 is manufactured by cutting a glass tube into a ring, the cross-sectional shape in the radial direction of the ring body 27 is formed in a rectangular shape (in some cases, a square shape) as shown in FIG. Right corners C are formed at the four corners. As an example, the outer dimensions of the ring body 27 are about 1.5 to 2.0 mm in thickness, about 20 mm in inner diameter, and about 21.5 to 22 mm in outer diameter.

Next, as shown in FIG. 7, while rotating the ring body 27 about the axis, the four corners C of the ring body 27 are melted by heating means 56 such as a heater or a burner over the entire circumference. ,cool. The glass at each corner C of the ring body 27 that has flowability due to the heating and melting is rounded by surface tension, and is cooled and solidified in that state, and as shown in FIG.
The cross-sectional shape along the radial direction of each corner portion C is formed in an arc shape (corner portion curved surface forming step). The length L from each end face of the ring body 27 in this arc-shaped region (arc-shaped region) can be controlled by the temperature and time of heating and melting.
Generally, it is about 200 to 400 microns.

Next, as shown in FIG. 9, both end faces 27a of the ring body 27 are ground and flattened so that a part of the arc-shaped region remains at each corner C, and a predetermined shape conforming to the product standard is obtained. Ring body 2 of thickness T (about 1.5 to 2.0 mm)
7 (grinding process at both ends). As in the present embodiment,
The method of once rounding each corner portion C by melting and then grinding both end surfaces 27a of the ring body 27, the both end surfaces (ground surfaces) 27a to be ground, and the peripheral surfaces of the both end surfaces 27a and the ring body 27 Since the angle θ between the tangent D at the joint between the (inner and outer peripheral surfaces) becomes an obtuse angle exceeding 90 degrees, the joint becomes an angle as in the related art, As compared to the case, there is an effect that chipping is less likely to occur and breakage or loss is less likely to occur. For the same reason, even when the both end surfaces 27a of the ring body 27 are ground, the position of the joining portion gradually changes due to the grinding. Therefore, there is also an effect that the chipping by the grinding tool is hardly generated at the joint portion at the corner. Usually, the grinding allowance (the hatched portion in FIG. 9) of both end surfaces of the ring body 27 is about 5 to 20 microns, which is within the range of the arc-shaped region.

Further, as a subsequent step, for example, a step of forming both end faces 27a of the ring body 27 which are in contact with the media on a rough surface, and in some cases, a film formation for forming a coating such as a conductive layer on the surface of the ring body 27 The glass spacer 26 is completed through a process and a cleaning process. The function of the conductive layer is to transfer static electricity charged on the medium 22 by friction with air due to high-speed rotation to the spacer 26 and the rotating column 1.
This is because the structure allows the structure to escape to the chassis 12 via the base 4.

(Second Embodiment) The manufacturing method of the glass spacer for media of the present embodiment is different from the manufacturing method of the first embodiment in that the above-described corner portion curved surface forming step and both end surface grinding are performed. The contents of the steps are different, and the other steps are the same. Only the different steps will be described with reference to FIGS. First, the corner portion curved surface forming step will be described. First, the molding device 50 used in this step will be described. This forming device 50 is a device for forming a corner C of the ring body 27 into a curved surface. This molding device 50 has an upper molding die (only an upper die) in which a ring-shaped first concave portion (the outer peripheral diameter and the inner peripheral diameter are dimensions that the ring body 27 just fits) is formed on the lower surface. ) 52 and a lower forming die (also referred to simply as a lower die) 54a formed with a ring-shaped second concave portion 54a (the outer peripheral diameter and the inner peripheral diameter are dimensions that the ring body 27 just fits) on the upper surface. ) 54, the first recess 52a and the second recess 54
a shows the first recess 5 when the upper mold 52 and the lower mold 54 are clamped.
The volume of the internal space is adjusted to the volume of the ring body 27 so that the overall shape of the ring-shaped internal space formed by the 2a and the second concave portion 54a is substantially the same as the outer shape of the ring body 27.

However, since the cross-sectional shape along the radial direction of the corner C of the ring body 27 is formed into an arc shape, the corner E of the inner surface of each of the recesses 52a and 54a is previously formed in a cross-sectional shape along the radial direction. Are formed in an arc shape. As an example, in FIG. 10, it is formed in an arc of radius R. In addition, upper mold 5
In the vicinity of the corner portion E on the inner upper surface of the second concave portion 52a, the heated and softened ring body 27 is provided with the upper mold 52 and the lower mold 54.
A sub-concave portion 52b is formed along the circumferential direction of the first concave portion 52a for allowing the surplus glass in the corner portion C of the ring body 27 to escape when the molding is performed by clamping with the above. Similarly, a corner portion E on the inner lower surface of the second concave portion 54a of the lower mold 54 is formed.
A sub recess 52b is also formed in the vicinity.

Next, the operation of forming the ring body 27 using the above-described forming apparatus 50 and forming the cross-sectional shape of each corner C of the ring body 27 into an arc shape will be described. First, as shown in FIG. 10, the ring 27 is inserted between the upper mold 52 and the lower mold 54 of the molding apparatus 50, and the glass ring 2
The temperature is set to a temperature at which 7 softens. Next, as shown in FIG. 11, the upper die 52 and the lower die 54 are clamped, and pressure is applied to the ring body 27 by the two dies 52, 54 to form the ring body 27. As described above, the first concave portion 52 of the upper die 52 in which the ring body 27 is housed.
a and the entire shape of the internal space formed between the second concave portion 54a of the lower mold 54 is substantially the same as the ring body 27, that is, the inner diameter and the outer diameter are substantially the same, and the thickness is substantially the same. The four corners C of the body 27 are formed in contact with the corresponding corners E of the first recess 52a and the second recess 54a,
The cross-sectional shape is formed in an arc. Then, since the corner portion C, whose cross-sectional shape was originally a right angle, is formed into an arc of a cross section, the cross-sectional area of the corner portion C of the ring body 27 is reduced, and the glass of that portion is left. The surplus glass escapes into a sub-recess 52b provided in advance in the first and second recesses 52a and 54a. Thereafter, the temperature atmosphere is lowered to normal temperature, the ring body 27 is cooled and solidified, the mold is opened as shown in FIG.

Next, the step of grinding both end faces will be described.
In this step, both end surfaces 27a of the ring body 27 are ground and flattened. The ring body 27 is formed by the forming device 50 as shown in FIG.
The corner C is formed in an arc of a cross section, and the inner peripheral surface 27b, the outer peripheral surface 27c, and both end surfaces 2 are formed.
The portion other than the region corresponding to the sub-recess 52b of 7a is formed in a plane. For this reason, when grinding both end surfaces 27a in this step, a projection formed so that surplus glass escapes into the sub concave portion 52b when the corner portion C is formed into a circular arc in section and protrudes from the both end surfaces 27a. Only the portion 27d (shaded portion in FIG. 12) may be ground.
As a result, both end surfaces 27a coincide with the tangents of the corners C formed in an arc of a cross section, so that the ring body 27 having no corners at the surface can be obtained.

It should be noted that the ring member 27 depends on molding conditions.
Some irregularities may also be formed in areas other than the above-described protrusions 27d on both end faces 27a of the first embodiment, but in this case, the same as the contents of the both end face grinding step of the first embodiment are performed. As shown in FIG.
a may be ground to such an extent that these irregularities are completely eliminated.
In this case, the both end surfaces 27a after the grinding do not coincide with the tangent line of the corner C, but the angle formed by the tangent line and the both end surfaces 27a at the joint portion between the both end surfaces 27a and the corner portion C is an obtuse angle. Therefore, there is an effect that the corner portion C is less likely to be chipped as compared with a state where the corner portion remains at a right angle.

The following is a description of the glass constituting the ring body 27. (1) Normal glass (soda glass): Main component is sodium oxide, calcium oxide, silicon dioxide. (2) Lead glass: Main component is lead oxide, potassium oxide, silicon dioxide. (3) Hard secondary glass: The main components are sodium oxide, boron oxide, aluminum oxide, and silicon dioxide. (4) Hard primary glass: The main components are sodium oxide, boron oxide, aluminum oxide, and silicon dioxide.

Further, conductive glass may be used as the glass material. In this case, it is not necessary to form the above-mentioned conductive coating layer on the surface, and the manufacturing process can be simplified.
Note that the conductive glass can be manufactured by mixing a conductive substance such as a niobium-based substance into glass, for example. As described above, various preferred embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments.
Of course, many modifications can be made without departing from the spirit of the invention.

[0022]

According to the method for manufacturing a glass spacer for media according to the present invention, each corner portion of the glass spacer has its original rectangular cross section along the radial direction formed by heat melting or molding over the entire circumference. Since it is formed in an arc shape from the shape, even if the corner portion comes into contact with another member and receives an impact force, it is less likely to be chipped as compared with a conventional state in which the corner portion remains in a rectangular shape. Therefore, it is possible to reduce the generation of glass chips due to chipping of the corners of the spacer.
There is an effect that it is possible to suppress the occurrence of an error when writing data to the medium or reading data from the medium due to glass dust falling on the surface of the medium of the hard disk device.

[Brief description of the drawings]

FIG. 1 is a partial cutaway explanatory view showing a general fixing structure of a medium in a hard disk device.

FIG. 2 is a plan view showing an outer shape of a spacer used in FIG. 1;

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a plan view showing the outer shape of the clamp used in FIG. 1;

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 is a cross-sectional view taken along a radial direction of the ring body for describing a grinding process of both end surfaces of the ring body serving as a base of the spacer used in FIG. 1;

FIG. 7 is an explanatory diagram for explaining a corner portion curved surface forming step in the steps of the first embodiment of the method of manufacturing the media glass spacer according to the present invention.

8 is a cross-sectional view of a ring body in which a corner portion C is formed in an arc-shaped cross section by the corner portion curved surface forming step of FIG. 7;

FIG. 9 is an explanatory view for explaining a step of grinding both end faces among the steps of the first embodiment of the method of manufacturing the glass spacer for media according to the present invention.

FIG. 10 is an explanatory view for explaining a corner portion curved surface forming step (step of forming a ring body between an upper die and a lower die) in a method of manufacturing a glass spacer for media according to the second embodiment of the present invention; State).

FIG. 11 is an explanatory view for explaining a corner-portion curved surface forming step (step of forming a ring body between an upper mold and a lower mold) in a method of manufacturing a glass spacer for media according to the second embodiment of the present invention; Mold clamped).

FIG. 12 is an explanatory view for explaining a step of grinding both end faces in the steps of the second embodiment of the method for manufacturing a glass spacer for media according to the present invention.

[Explanation of symbols]

 14 Rotating Column 22 Media 26 Glass Spacer 27 Ring Body C Corner

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 1, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Method for manufacturing glass spacer for media

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a glass spacer for a medium, which is mounted together with a plurality of media on a rotating column provided in a hard disk drive.

[0002]

2. Description of the Related Art A plurality of media (referred to as magnetic disk media having a magnetic layer for storing data on the surface) of a hard disk drive are mounted together with a glass spacer for media (also simply referred to as a spacer). The structure of the rotating column will be described with reference to FIG. 10
Reference numeral denotes an electric motor, and the outer shape of the hard disk device is fixed to a part of a chassis 12 formed in a box shape. 1
Reference numeral 4 denotes a rotating column attached to the rotating shaft 16 of the electric motor 10. A flange portion 18 is formed at an end (lower end) of the rotating column 14 on the chassis 12 side. In addition, a female screw hole 20 is provided on the upper surface of the rotating column 14.

Reference numeral 22 denotes a medium which is formed in a thin disk shape using a glass material. A mounting hole 24 having a diameter slightly larger than the outer diameter of the rotary column
The rotary column 14 is inserted into the mounting hole 24, and is mounted on the rotary column 14 in a state where the rotary column 14 is externally fitted to the rotary column 14. The medium 22 has a magnetic layer (not shown) formed by coating a magnetic material on both end surfaces (upper and lower surfaces in FIG. 1).
Data recording is performed, and the recorded data is read out.

Reference numeral 26 denotes a spacer. This spacer 26
2 and 3 are formed in a ring shape that can be externally fitted to the rotating column 14, and are provided on the rotating column 14 together with the plurality of media 22, between the media 22, and between the media 22 and a clamp described later. The medium 22 is provided with a predetermined interval (for example, 1.5 to 2.0 mm) between the media 22. The spacer 26 is
As an example, a ring body formed by cutting a glass tube into a predetermined thickness, and flattening by grinding and polishing both end surfaces thereof, and a grinding process for making both end surfaces parallel to each other,
It is manufactured by performing a roughening process for roughening both end surfaces and a cleaning process. The inner diameter of the spacer 26 is formed slightly larger than the outer diameter of the rotating column 14, and the outer diameter is formed to be substantially the same as the outer diameter of the flange portion 18 of the rotating column 14. 28
Is a clamp, which is a member for fixing the medium 22 to the rotating column 14. This clamp 28 is shown in FIGS.
Is formed in a thin disk shape having substantially the same outer diameter as the spacer 26, and a through hole 30 is provided in a central portion thereof,
A concave groove 32 is provided around the outer edge along the circumferential direction.

[0005] Then, as shown in FIG.
After the plurality of media 22 and the spacers 26 are externally fitted in a state of being alternately stacked on the rotating column 14, they are fixed to the upper surface of the rotating column 14 using a male screw 34. At this time, the lower end of the concave groove 32 presses the spacer 26 disposed at the uppermost position downward, so that the plurality of media 22 and the spacer 26 are sandwiched between the clamp 28 and the flange portion 18 and Will be fixed. When the clamp 28 is screwed by the male screw 34, the central portion is dented and elastically deformed, and the elastic force of the elastic deformation presses the spacer 26 abutting the concave groove 32 downward.

Conventionally, the spacer 26 and the clamp 28 have been formed using a metal material. However, in recent years, the medium itself may be manufactured using glass. In such a case, the medium is closely adhered to the medium. If the coefficient of thermal expansion between the spacer and the spacer is different, the stress acts on the medium due to the temperature change and the medium is distorted.
In order to avoid such a problem that an error occurs at the time of data recording or reading by the method 5 and the reliability of the hard disk device is reduced, the spacer itself is also made of glass and the thermal expansion coefficient of the medium 22 is made uniform. It has become.

[0007]

However, the above-mentioned conventional glass spacer has the following problems. When the spacer 26 is manufactured, both end faces of the ring body that are in contact with the media 22 and the clamp 28 need to be flattened, and the end faces are ground and polished. Since the ring body 27 is formed by cutting a glass tube into a circle, the cross-sectional shape along the radial direction is rectangular or square as shown in FIG. Therefore, the four corners of the cross section, that is, both end surfaces 27a and the inner peripheral surface 27b which are sequentially ground, and both end surfaces 27a and the outer peripheral surface 27c
Since the joining portion (corner portion) C is always substantially at a right angle, there is a problem that it is easily chipped during grinding or polishing. Even if the corner portion is not chipped in the grinding / polishing process, the cross-sectional shape along the radial direction of the manufactured spacer 26 has four right angles and the tip is sharp, so that the material may be glass. Yes, spacer 2
6, when it comes into contact with other members when it is mounted on the rotary column 14, or when it is pressed by the clamp 28 after being mounted on the rotary column 14, There is a problem that C is easily missing.

Therefore, in the related art, there is a case where the corner portion C is further subjected to a polishing process to perform chamfering to eliminate a sharp portion. However, since the tip of the corner portion C is originally sharp as described above, this polishing process is performed. There is also a problem that the corner C is easily chipped.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method for manufacturing a glass spacer for a medium, which has a corner portion which is not easily chipped.

[0010]

The present invention has the following arrangement to achieve the above object. That is, the contract of the present invention
The invention according to claim 1 has a ring-shaped outer shape, is interposed between a plurality of media externally fitted to the rotating column and mounted on the rotating column, and a gap having a predetermined interval between the media. the method of manufacturing a glass spacer medium to form and forming a ring body using glass, directly heating and melting the corner of the ring member, the cross section along the radial direction of the corner portion over the entire circumference Forming a shape in an arc,
Grinding the two end faces of the ring body to flatten them while leaving the arcuate portions of the corners. The invention according to claim 2 of the present invention.
Has a ring-like outer shape and is fitted around the
It is interposed between a plurality of media mounted on
Media glass that forms a predetermined gap between media
In the method for manufacturing spacers, a ring
A step of forming a body and a state in which the entire ring body is softened
And mold the ring around the corners of the ring.
Forming an arc-shaped cross section along the radial direction,
With the arc portion of the corner part left, the ring
Grinding and flattening both end faces of the body
It is characterized by. According to this configuration, the cross-sectional shape along the radial direction of each corner portion of the glass spacer is formed in an arc shape from the original right-angled shape by heat melting or molding over the entire circumference. Therefore, even if the corner portion receives an impact force due to contact with another member or the like, the corner portion is less likely to be chipped as compared with a state in which the corner portion remains in a right angle shape.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method for manufacturing a glass spacer for media according to the present invention will be described below in detail with reference to the accompanying drawings. The same components as those described in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. (First Embodiment) First, a glass ring body 27
Is formed (manufactured) (ring body forming step). By subjecting the ring body 27 to a grinding process, a polishing process, a surface roughening process, and, in some cases, a film forming process, a spacer 26 having a predetermined thickness and a predetermined surface roughness is finally obtained. . Since the ring body 27 is manufactured by cutting a glass tube into a ring, the cross-sectional shape in the radial direction of the ring body 27 is formed in a rectangular shape (in some cases, a square shape) as shown in FIG. Right corners C are formed at the four corners. As an example, the outer dimensions of the ring body 27 are about 1.5 to 2.0 mm in thickness, about 20 mm in inner diameter, and about 21.5 to 22 mm in outer diameter.

Next, as shown in FIG. 7, while rotating the ring body 27 about the axis, the four corners C of the ring body 27 are melted by heating means 56 such as a heater or a burner over the entire circumference. ,cool. The glass at each corner C of the ring body 27 that has flowability due to the heating and melting is rounded by surface tension, and is cooled and solidified in that state, and as shown in FIG.
The cross-sectional shape along the radial direction of each corner portion C is formed in an arc shape (corner portion curved surface forming step). The length L from each end face of the ring body 27 in this arc-shaped region (arc-shaped region) can be controlled by the temperature and time of heating and melting.
Generally, it is about 200 to 400 microns.

Next, as shown in FIG. 9, both end faces 27a of the ring body 27 are ground and flattened so that a part of the arc-shaped region remains at each corner C, and a predetermined shape conforming to the product standard is obtained. Ring body 2 of thickness T (about 1.5 to 2.0 mm)
7 (grinding process at both ends). As in the present embodiment,
The method of once rounding each corner portion C by melting and then grinding both end surfaces 27a of the ring body 27, the both end surfaces (ground surfaces) 27a to be ground, and the peripheral surfaces of the both end surfaces 27a and the ring body 27 Since the angle θ between the tangent D at the joint between the (inner and outer peripheral surfaces) becomes an obtuse angle exceeding 90 degrees, the joint becomes an angle as in the related art, As compared to the case, there is an effect that chipping is less likely to occur and breakage or loss is less likely to occur. For the same reason, even when the both end surfaces 27a of the ring body 27 are ground, the position of the joining portion gradually changes due to the grinding. Therefore, there is also an effect that the chipping by the grinding tool is hardly generated at the joint portion at the corner. Usually, the grinding allowance (the hatched portion in FIG. 9) of both end surfaces of the ring body 27 is about 5 to 20 microns, which is within the range of the arc-shaped region.

Further, as a subsequent step, for example, a step of forming both end faces 27a of the ring body 27 which are in contact with the media on a rough surface, and in some cases, a film formation for forming a coating such as a conductive layer on the surface of the ring body 27 The glass spacer 26 is completed through a process and a cleaning process. The function of the conductive layer is to transfer static electricity charged on the medium 22 by friction with air due to high-speed rotation to the spacer 26 and the rotating column 1.
This is because the structure allows the structure to escape to the chassis 12 via the base 4.

(Second Embodiment) The manufacturing method of the glass spacer for media of the present embodiment is different from the manufacturing method of the first embodiment in that the above-described corner portion curved surface forming step and both end surface grinding are performed. The contents of the steps are different, and the other steps are the same. Only the different steps will be described with reference to FIGS. First, the corner portion curved surface forming step will be described. First, the molding device 50 used in this step will be described. This forming device 50 is a device for forming a corner C of the ring body 27 into a curved surface. This molding device 50 has an upper molding die (only an upper die) in which a ring-shaped first concave portion (the outer peripheral diameter and the inner peripheral diameter are dimensions that the ring body 27 just fits) is formed on the lower surface. ) 52 and a lower forming die (also referred to simply as a lower die) 54a formed with a ring-shaped second concave portion 54a (the outer peripheral diameter and the inner peripheral diameter are dimensions that the ring body 27 just fits) on the upper surface. ) 54, the first recess 52a and the second recess 54
a shows the first recess 5 when the upper mold 52 and the lower mold 54 are clamped.
The volume of the internal space is adjusted to the volume of the ring body 27 so that the overall shape of the ring-shaped internal space formed by the 2a and the second concave portion 54a is substantially the same as the outer shape of the ring body 27.

However, since the cross-sectional shape along the radial direction of the corner C of the ring body 27 is formed into an arc shape, the corner E of the inner surface of each of the recesses 52a and 54a is previously formed in a cross-sectional shape along the radial direction. Are formed in an arc shape. As an example, in FIG. 10, it is formed in an arc of radius R. In addition, upper mold 5
In the vicinity of the corner portion E on the inner upper surface of the second concave portion 52a, the heated and softened ring body 27 is provided with the upper mold 52 and the lower mold 54.
A sub-concave portion 52b is formed along the circumferential direction of the first concave portion 52a for allowing the surplus glass in the corner portion C of the ring body 27 to escape when the molding is performed by clamping with the above. Similarly, a corner portion E on the inner lower surface of the second concave portion 54a of the lower mold 54 is formed.
A sub recess 52b is also formed in the vicinity.

Next, the operation of forming the ring body 27 using the above-described forming apparatus 50 and forming the cross-sectional shape of each corner C of the ring body 27 into an arc shape will be described. First, as shown in FIG. 10, the ring 27 is inserted between the upper mold 52 and the lower mold 54 of the molding apparatus 50, and the glass ring 2
The temperature is set to a temperature at which 7 softens. Next, as shown in FIG. 11, the upper die 52 and the lower die 54 are clamped, and pressure is applied to the ring body 27 by the two dies 52, 54 to form the ring body 27. As described above, the first concave portion 52 of the upper die 52 in which the ring body 27 is housed.
a and the entire shape of the internal space formed between the second concave portion 54a of the lower mold 54 is substantially the same as the ring body 27, that is, the inner diameter and the outer diameter are substantially the same, and the thickness is substantially the same. The four corners C of the body 27 are formed in contact with the corresponding corners E of the first recess 52a and the second recess 54a,
The cross-sectional shape is formed in an arc. Then, since the corner portion C, whose cross-sectional shape was originally a right angle, is formed into an arc of a cross section, the cross-sectional area of the corner portion C of the ring body 27 is reduced, and the glass of that portion is left. The surplus glass escapes into a sub-recess 52b provided in advance in the first and second recesses 52a and 54a. Thereafter, the temperature atmosphere is lowered to normal temperature, the ring body 27 is cooled and solidified, the mold is opened as shown in FIG.

Next, the step of grinding both end faces will be described.
In this step, both end surfaces 27a of the ring body 27 are ground and flattened. The ring body 27 is formed by the forming device 50 as shown in FIG.
The corner C is formed in an arc of a cross section, and the inner peripheral surface 27b, the outer peripheral surface 27c, and both end surfaces 2 are formed.
The portion other than the region corresponding to the sub-recess 52b of 7a is formed in a plane. For this reason, when grinding both end surfaces 27a in this step, a projection formed so that surplus glass escapes into the sub concave portion 52b when the corner portion C is formed into a circular arc in section and protrudes from the both end surfaces 27a. Only the portion 27d (shaded portion in FIG. 12) may be ground.
As a result, both end surfaces 27a coincide with the tangents of the corners C formed in an arc of a cross section, so that the ring body 27 having no corners at the surface can be obtained.

It should be noted that the ring member 27 depends on molding conditions.
Some irregularities may also be formed in areas other than the above-described protrusions 27d on both end faces 27a of the first embodiment, but in this case, the same as the contents of the both end face grinding step of the first embodiment are performed. As shown in FIG.
a may be ground to such an extent that these irregularities are completely eliminated.
In this case, the both end surfaces 27a after the grinding do not coincide with the tangent line of the corner C, but the angle formed by the tangent line and the both end surfaces 27a at the joint portion between the both end surfaces 27a and the corner portion C is an obtuse angle. Therefore, there is an effect that the corner portion C is less likely to be chipped as compared with a state where the corner portion remains at a right angle.

The following is a description of the glass constituting the ring body 27. (1) Normal glass (soda glass): Main component is sodium oxide, calcium oxide, silicon dioxide. (2) Lead glass: Main component is lead oxide, potassium oxide, silicon dioxide. (3) Hard secondary glass: The main components are sodium oxide, boron oxide, aluminum oxide, and silicon dioxide. (4) Hard primary glass: The main components are sodium oxide, boron oxide, aluminum oxide, and silicon dioxide.

Further, conductive glass may be used as the glass material. In this case, it is not necessary to form the above-mentioned conductive coating layer on the surface, and the manufacturing process can be simplified.
Note that the conductive glass can be manufactured by mixing a conductive substance such as a niobium-based substance into glass, for example. As described above, various preferred embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments.
Of course, many modifications can be made without departing from the spirit of the invention.

[0022]

According to the method for manufacturing a glass spacer for media according to the present invention, each corner portion of the glass spacer has its original rectangular cross section along the radial direction formed by heat melting or molding over the entire circumference. Since it is formed in an arc shape from the shape, even if the corner portion comes into contact with another member and receives an impact force, it is less likely to be chipped as compared with a conventional state in which the corner portion remains in a rectangular shape. Therefore, it is possible to reduce the generation of glass chips due to chipping of the corners of the spacer.
There is an effect that it is possible to suppress the occurrence of an error when writing data to the medium or reading data from the medium due to glass dust falling on the surface of the medium of the hard disk device.

[Brief description of the drawings]

FIG. 1 is a partial cutaway explanatory view showing a general fixing structure of a medium in a hard disk device.

FIG. 2 is a plan view showing an outer shape of a spacer used in FIG. 1;

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a plan view showing the outer shape of the clamp used in FIG. 1;

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 is a cross-sectional view taken along a radial direction of the ring body for describing a grinding process of both end surfaces of the ring body serving as a base of the spacer used in FIG. 1;

FIG. 7 is an explanatory diagram for explaining a corner portion curved surface forming step in the steps of the first embodiment of the method of manufacturing the media glass spacer according to the present invention.

8 is a cross-sectional view of a ring body in which a corner portion C is formed in an arc-shaped cross section by the corner portion curved surface forming step of FIG. 7;

FIG. 9 is an explanatory view for explaining a step of grinding both end faces among the steps of the first embodiment of the method of manufacturing the glass spacer for media according to the present invention.

FIG. 10 is an explanatory view for explaining a corner portion curved surface forming step (step of forming a ring body between an upper die and a lower die) in a method of manufacturing a glass spacer for media according to the second embodiment of the present invention; State).

FIG. 11 is an explanatory view for explaining a corner-portion curved surface forming step (step of forming a ring body between an upper mold and a lower mold) in a method of manufacturing a glass spacer for media according to the second embodiment of the present invention; Mold clamped).

FIG. 12 is an explanatory view for explaining a step of grinding both end faces in the steps of the second embodiment of the method for manufacturing a glass spacer for media according to the present invention.

[Description of Signs] 14 Rotating Column 22 Media 26 Glass Spacer 27 Ring Body C Corner

Claims (1)

[Claims] 1. A medium having a ring-shaped outer shape, which is interposed between a plurality of media which are externally fitted to a rotating column and mounted on the rotating column, and which form a predetermined gap between the media. In the method for manufacturing a glass spacer for media, a step of forming a ring body using glass, and a step of directly heating and melting a corner portion of the ring body, or performing die molding while the entire ring body is softened. Forming an arc-shaped cross-section along the radial direction over the entire circumference of the corner portion; and grinding and flattening both end surfaces of the ring body while leaving the arc-shaped portion of the corner portion. A method for producing a glass spacer for media, comprising: