JP3398947B2 - Mold device for shutter molding of recording disk - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold device for molding a shutter of a recording disk for molding a resin shutter such as a micro floppy disk.

[0002]

2. Description of the Related Art As shown in FIG. 4, a micro-floppy disk has a magnetic disk 3 built in a shell case 2 having an opening window 1 and a shutter 4 slidably mounted on the shell case 2 to provide a magnetic disk. The opening window 1 for exposing a part of 3 is opened and closed. The shutter 4 is formed in a substantially U-shaped cross section by a pair of main plate portions 5 that face each other with a small gap therebetween and a connecting portion 6 that integrally connects the edge portions of the main plate portions 5 to each other. Opening windows 7 that overlap the opening windows 1 of the shell case 2 are formed in the main plate portions 5 respectively. The shutter 1 may be made by pressing a metal plate,
Some are made of resin integrally molded. For its molding,
Injection molding is commonly used. FIG. 5 shows a cross-sectional view of an example of the shutter 4 made of resin, but as shown in the figure, the inner surface of the main plate portion 5 and the connecting portion 6 of the shutter 4 is
Protrusions 8 and 9 for assembling the shutter 4 to the shell case 2 are formed. An opening hole 10 for die cutting, which is necessary to form the protrusions 8 and 9, is formed in the edge portion of the main plate portion 5 on the connecting portion 6 side.

As described above, since the pair of main plate portions 5 of the shutter 4 face each other with a small gap therebetween, the center core, which is a mold member forming the inner surface of the shutter 4, is very thin. Will be things. Moreover, in this center core, at least the edge forming the connecting portion 6 is a free end. Conventionally, as the material of the center core, a stainless steel hardened steel (for example, HPM38 manufactured by Hitachi Metals) made of an ingot which is generally used as a die material has been used. The rate is about 2100 kgf / mm2.

[0004]

By the way, when resin is filled in a cavity formed in a mold apparatus in which the mold is closed, a high pressure is applied to the cavity, and the center core is, for example, 500 to 600 kg. The load is too high. Therefore, the center core made of the hardened steel of the conventional ingot material is likely to be tilted or bent by the resin pressure. For example, if the center core tilts, both main plate portions 5 of the shutter 4
Variation occurs in the thickness, resulting in defective molding. In particular, the thickness of the main plate 5 is 0.4 mm, which is very thin by regulation,
A slight variation in thickness causes molding failure. Even in the conventional shutter molding die device, the center core and the slide core forming the outer surface of the main plate portion 5 abut against each other at the portions corresponding to the opening window 7 and the opening hole 10. Cannot be sufficiently prevented, and if the slide core hits the center core, the center core may be deformed undesirably. If, for example, even a part of the main plate portion 5 has a portion thicker than the regulation, it is a defective product.

The present invention is intended to solve such a problem, and can prevent the center core from tilting or bending,
An object of the present invention is to provide a mold device for molding a shutter of a recording disk, which is capable of molding a shutter having a main plate portion having a specified thickness.

[0006]

According to a first aspect of the present invention, there is provided a mold device for molding a shutter for a recording disk, comprising: a pair of main plate portions facing each other with a small gap therebetween in order to achieve the above object. In a mold device for molding a shutter including a connecting portion that integrally connects the edge portions of the main plate portion to each other,
Movable mold has a center core of the core holder and this is fixed to form the inside surface of the Shah <br/> Potter Young's modulus is more formed on 2,500 kgf / mm ² or more materials, the Koahoru
In the dar, a pair of slide cores are orthogonal to the main plate portion.
Can be slidably attached in any direction, and the core holder
On both sides of the center core and the slide core
A pair of side cores are provided along the surface,
The side cores are both side edges of the flat plate portion 18 of the center core.
It fits into the part .

The factors relating to the bending of the center core when the molding material is filled are the load applied to the center core by the pressure of the molding material, the fixing point of the center core, the shape and elasticity. For example, the larger the cross-sectional shape of the center core is, the smaller the bending becomes, but the cross-sectional shape of the center core is determined by the shape of the shutter to be molded, and therefore cannot be changed. Also, the more the center core fixed points are in the short span, the smaller the deflection becomes, but the shape of the shutter inevitably causes one edge of the center core to be a free end.
There are restrictions on the setting of fixed points. Furthermore, the pressure of the molding material should be determined so as not to cause defective filling depending on the conditions such as the viscosity of the molding material and the shape of the shutter, which are defined by the product specifications, and therefore cannot be lowered. From the above, it is the elasticity of the material of the center core that can be freely set among the various factors relating to the bending of the center core. And the Young's modulus of the material of the center core
If it is 2500 kgf / mm ² or more, the inclination and bending of the center core can be reduced to an acceptable level, and thus a shutter having a main plate portion with a specified thickness can be molded.

As a material for the center core, specifically, powdered high speed steel as in the invention of claim 2 or cemented carbide as in the invention of claim 3 is suitable.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a shutter molding die apparatus for a recording disk according to the present invention will be described below with reference to the drawings. In this embodiment, the molded shutter 4 is the same as that shown in FIGS. 4 and 5 described above, and therefore, corresponding parts will be denoted by the same reference numerals and description thereof will be omitted.

Reference numeral 11 is a fixed die, and 12 is a movable die. These fixed die 11 and movable die 12 move in the vertical direction shown in FIGS. 2 and 3 (hereinafter referred to as the main die opening / closing direction) to open and close. A cavity 13 in the shape of the shutter 4 is formed between the two when the mold is closed. The main mold opening / closing direction is set to be a direction orthogonal to the connecting portion 6 of the shutter 4 and along the main plate portion 5. The fixed mold 11 is a cavity block that forms the outer surface of the connecting portion 6.
Have 14. The cavity block 14 is provided with a gate 15 which is a resin injection port into the cavity 13.

The movable die 12 has a core holder 16 and a center core 17 fixed to the core holder 16, and the center core 17 has a thin flat plate portion 18 forming the inner surface of the shutter 4. ing. And this center core
The material of 17 is powder high speed steel (high speed steel by powder metallurgy), and its Young's modulus is about 2600 kgf / mm ² .

A pair of slide cores 19 are attached to the core holder 16 so as to be slidable in a direction orthogonal to the main plate portion 5 of the shutter 4. Both of these slide cores 19
Form the outer surfaces of the two main plate portions 5, respectively. A convex portion 20 for forming the opening window 7 of the main plate portion 5 is formed on one or both of the facing surfaces of the slide core 19 and the center core 17. Along with this, slide core 19
A convex portion 21 for forming the opening hole 10 of the main plate portion 5 and the protrusions 8 and 9 is formed on the. Further, each slide core 19 is formed with a core holder facing surface 22 facing the center core 17 side. On the other hand, the core holder 16 is formed with a pair of slide core facing surfaces 23 that face the core holder facing surfaces 22 of the slide cores 19, respectively. further,
The core holder 16 is provided with a pair of side cores 24 along both side surfaces of the center core 17 and the slide core 19, that is, the surfaces parallel to the sliding direction of the slide core 19 and the main mold opening / closing direction.

A spring 25 is provided between the facing surfaces 22 and 23 of the core holder 16 and the slide core 19 for opening the slide core 19 with respect to the center core 17 as the mold is opened. On the other hand, the fixed mold 11 is provided with a locking block 26 for pressing the slide core 19 and closing the center core 17 when the mold is closed. In this locking block 26, an inclined surface 27 inclined in a predetermined direction with respect to the main mold opening / closing direction abuts an inclined surface 28 formed on the slide core 19.

Further, each of the side cores 24 is formed with a groove-shaped recess 32 into which both side edge portions 31 of the flat plate portion 18 of the center core 17 are fitted. Also, the core holder 16
On both sides of both slide cores 19 slidably assembled to each other, step-shaped abutting portions 33 orthogonal to the sliding direction of these slide cores 19 and facing the center core 17 side are formed. On the other hand, the surface of the side core 24 orthogonal to the sliding direction of the core holder 16 forms a receiving portion 34 against which the abutting portions 33 of the slide core 19 abut when the mold is closed.
That is, when the cavity block 14 (see FIG. 8) on the fixed mold 2 side presses the slide core 19 in the mold closed state, the abutting portions 33 of the slide core 19 come into contact with the receiving portions 34 of the side cores 24, respectively. ing.

Further, convex portions 41 are formed on both ends of the surface of the flat plate portion 18 of the center core 17 on the side of the cavity block 14, respectively. These convex portions 41 are located outside the portion of the flat plate portion 18 that forms the shutter 4.
On the other hand, the cavity block 14 is formed with a pair of concave portions 42 into which the convex portions 41 of the center core 17 are fitted when the mold is closed. The convex portion 41 and the concave portion 42 may be tapered so that they can be fitted smoothly when the mold is closed.

Further, at the position on the cavity block 14 side of both slide cores 19, a stepped abutting portion 43 which is orthogonal to the sliding direction of these slide cores 19 and faces the center core 17 side is formed by a convex portion. ing. On the other hand, the cavity block 14 is formed with a pair of receiving portions 44, which the abutting portions 43 of the slide core 19 abut when the mold is closed, as stepped surfaces. That is, when the cavity block 14 on the fixed mold 2 side presses the slide core 19 in the mold closed state, the abutting portions 43 of the slide core 19 abut the receiving portions 44 of the cavity block 14, respectively.

On the other hand, when the mold is closed, the slide core 19
The dimensions are set so that a minute gap c of, for example, about 0.01 mm is formed between the center core 17 and the center core 17. This clearance c is to prevent the slide core 19 from abutting the center core 17 and interfering with the positioning of the side core 24 and the cavity block 14 with the center core 17, but within the range of the clearance c is a flat plate shape. Even if the part 18 bends,
It is set to a value that is acceptable as the product dimensional error.
Further, in the present embodiment, the dimensions are set so that the slide core surface 23 of the core holder 16 and the core holder surface 22 of the slide core 19 do not abut each other.

At the time of injection molding, a molten thermoplastic resin as a molding material is filled from the gate 15 into the cavity 13 in a mold closed state. Then, after the resin filled in the cavity 13, that is, the shutter 4 is cooled and solidified, the mold is opened. When this mold is opened, fixed mold 11 and movable mold 12
As the and are opened, the molded shutter 4 first separates from the fixed mold 11. In addition, as the fixed mold 11 and the movable mold 12 open, the force of the spring 25 causes the slide core to move.
19 moves in a direction away from the center core 17 with respect to the core holder 16, and separates from the main plate portion 5 of the shutter 4. Further, the shutter 4 is ejected to the fixed die 11 side by an ejection pin (not shown) provided on the movable die 12 side, separated from the center core 17, and taken out.

Thereafter, the mold is closed again and the molding is repeated. When the mold is closed, the locking block 26 has an inclined surface 2
By pushing the slide core 19 at 8 and 29, the slide core moves toward the center holder 17 with respect to the core holder 16, contrary to the mold opening.

When the cavity 13 is filled with resin as described above, the flat portion of the center core 17 is pressed by the pressure of the resin.
Although a large load is applied to 18, the center core 17 is made of powdered high-speed steel and its Young's modulus is as large as about 2600 kgf / mm2, so tilting and bending of the thin flat plate part 18 due to resin pressure are prevented. It As a result, the shutter 4 having the main plate portion 5 having the specified thickness is formed. That is,
It is possible to prevent variations in the thickness of both main plate portions 5 and to make the thickness of each main plate portion 5 uniform.

Further, by using powder high-speed steel as the material of the center core 17, it is possible to obtain the effect of improving the wear resistance and to secure the workability in the die manufacturing.

In addition, in the mold closed state, both side edge portions 31 of the flat plate-like portion 18 of the center core 17 are fitted in the recesses 32 of both side cores 24, respectively, and
Since the convex portions 41 at both ends of the surface of the flat plate portion 18 of the cavity block 14 side are fitted in the pair of concave portions 42 of the cavity block 14, respectively, the thin flat plate portion 18 due to the pressure of the resin is formed. The inclination and bending of the can be prevented more reliably.

Further, when the abutting portion 33 of the slide core 19 abuts the receiving portion 34 of the side core 24 in the mold closed state, the slide core 19 is positioned with respect to the side core 24. Further, as described above, since the center core 17 is positioned with respect to the side core 24 by fitting the side edge portion 31 thereof into the recess 32 of the side core 24, the slide core with respect to the center core 17 is slid. twenty four
Will be positioned. At the same time, the slide core 19 is positioned with respect to the cavity block 14 by the abutting portion 43 of the slide core 19 abutting the receiving portion 44 of the cavity block 14 in the mold closed state. Further, as described above, since the center core 17 is positioned with respect to the cavity block 14 by fitting the convex portion 41 into the concave portion 42 of the cavity block 14, the center core 17 slides with respect to the center core 17. core
24 will be positioned. In this way, the positioning of the center core 17 and the slide core 24 can be made more reliable, so that the accuracy of the thickness of the main plate portion 5 can be further improved.

As the material of the center core 17, a material other than the powder high speed steel of the above-mentioned embodiment can be used. For example, a cemented carbide, which is a powder metallurgy material containing a carbide of a refractory metal such as tungsten as a main component, is also suitable. The Young's modulus of the cemented carbide is extremely high at 4500 to 5000 kgf / mm ^2, and when the cavity 13 is filled with resin, the center core 17 can be more reliably prevented from tilting and bending, and the thickness of the main plate portion 5 of the shutter 4 can be increased. The accuracy of can be further improved. In addition, the cemented carbide also has the effect of improving wear resistance.

In any case, in order to sufficiently prevent the center core 17 from tilting or bending, the Young's modulus is 2500 kgf / mm ²
The above materials should be used.

Furthermore, the present invention is not limited to the above embodiment, but various modifications can be made. For example, in the above-described embodiment, the side edge portion 31 of the center core 17 is fitted into the recess 32 of the side core 24, and the slide core
The abutting portion 33 of the 19 is abutted against the receiving portion 34 of the side core 24, and the convex portion 41 of the center core 17 is fitted into the concave portion 42 of the cavity block 26, and the abutting portion 43 of the slide core 19 is fitted into the cavity block. By abutting against the receiving portion 44 of 26, the certainty of preventing the inclination and bending of the center core 17 is improved, but these configurations are not essential, and the material of the center core 17 as described above is not necessary. The inclination and bending of the center core 17 can be reduced to an acceptable level by only proper selection. Furthermore, in the above-mentioned embodiment, the shutter for MFD was described as an example, but the present invention is applicable to general shutters having the same shape and structure.

[0027]

According to the first aspect of the present invention, the shutter is provided with a pair of main plate portions that face each other with a small gap therebetween, and a connecting portion that integrally connects the edge portions of these main plate portions to each other. in the mold apparatus for molding a movable type, your core holder
And center it in a fixed form the inside surface of the shutter Yang <br/>'s modulus is more formed on 2,500 kgf / mm ² or more materials
-The core holder has a pair of slides
Assemble the core so that it can slide in the direction orthogonal to the main plate.
In addition, the core holder has the center core and
And a pair of supports along both sides of the slide core.
Id core is provided, and both side cores are
Since the cores are fitted to both side edges of the flat plate-shaped portion, it is possible to prevent the center core from tilting or bending due to the pressure of the molding material when the molding material is filled, and it is possible to mold the shutter having the main plate portion of the specified thickness.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, since the material of the center core is powdered high speed steel, the effect of abrasion resistance can be obtained and the workability can be secured. .

According to the invention of claim 3, in addition to the effect of the invention of claim 1, since the material of the center core is cemented carbide, the inclination and bending of the center core can be prevented more reliably, and Also, the effect of abrasion resistance can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view of a movable mold showing an embodiment of a mold device for molding a shutter of a recording disk of the present invention.

FIG. 2 is a sectional view of the same.

FIG. 3 is a perspective view of the above center core.

FIG. 4 is a perspective view of a micro floppy disk.

FIG. 5 is a sectional view of the same shutter.

[Explanation of symbols]

4 Shutter 5 Main plate 6 Connection 12 Movable 16 Core holder 17 Center core 18 Flat plate 19 Slide core 24 Side core 32 Recess

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI // B29L 17:00 B29L 17:00

Claims (3)

(57) [Claims] And 1. A small clearance the pair of main plate portion to face each other hold, the mold apparatus for molding a shutter and a connecting portion for connecting together mutually the edge portions of the main plate portion, the movable mold has a center core of the core holder and this is fixed to form the inside surface of the <br/> shutter Young's modulus is more formed on 2,500 kgf / mm ² or more materials, said core
The holder has a pair of slide cores orthogonal to the main plate portion.
Is slidable in the direction
The center includes the slide core and the slide core.
A pair of side cores are provided along both sides,
Both side cores are on both sides of the flat part of the center core.
A mold device for molding a shutter for a recording disk, which is fitted to an edge portion . 2. A mold device for molding a shutter for a recording disk according to claim 1, wherein the material of the center core is powder high speed steel. 3. The mold device for molding a shutter for a recording disk according to claim 1, wherein the material of the center core is cemented carbide.