JPH0232425Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to the structure of an ejector pin that releases a product in a mold for injection molding a disc-shaped recording medium (hereinafter referred to as a disk). This invention relates to a device in which an ejector pin can be moved and protruded and air can be blown out at the same time using air pressure.

[Prior Art] This type of disk has a thin disk shape as a whole and is composed of a central hole in the center, a clamping area around the hole, and a surrounding information track surface. At present, when releasing the mold, the ejector pin is advanced into the clamping area and protruded.

[Problems to be solved by the invention] When abutting with an ejector pin, the clamping area protrudes and the entire area becomes curved, so the information track surface is released from the stamper in an oblique state. However, it could not be adopted because the unevenness of the signal part would be damaged. In particular, since disks are required to have flatness within a certain tolerance for information reproducibility, it is necessary to completely prevent warping during demolding.

On the other hand, mold release using only air blowing is generally performed through minute gaps where the molten resin does not penetrate, so a sufficient amount of air blowing cannot be obtained.
It was insufficient.

Therefore, as shown in Japanese Patent Application Laid-Open No. 51-100154, a device that uses both ejector pin protrusion and air blowing requires its own control mechanism for pin protrusion and air blowing, and the structure is complicated. There were some drawbacks that made it complicated.

In the above combination protrusion, the ejector pin has a solid pin shape at the tip, but the applicability to a disk mold having a cut pin is not disclosed at all. In this case, Figure 4 of the above-mentioned publication and Jitsukō 43-
As shown in Publication No. 13756, a device that blows out air by protruding the tip of a solid pin that expands in an inverted umbrella shape has a high possibility of protruding the information track surface because the protruding area increases. It was deemed impossible to implement.

In any case, it cannot be applied directly to a disk mold, and with the structure as it is, it is not possible to secure a sufficient amount of air to prevent the disk from bending.

The present invention was developed in view of the above-mentioned circumstances, and aims to make it possible to simultaneously eject the ejector pin and blow out air using air pressure, thereby making it possible to release the disc without sacrificing accuracy. Its purpose is to

[Means for Solving the Problems] A mold for molding a disc-shaped recording medium according to the present invention to achieve the above object is provided with a cutter pin at the center of the movable template side of the disc molding space, and a cutter pin on the outer periphery of the cutter pin. The ejector pin is inserted into the ejector pin so that it can move forward and backward using air pressure.

The ejector pin includes a cylindrical piston with a large diameter provided at the rear end, and a cylindrical body portion provided in front of the piston and having a front half portion with a reduced diameter,
This body has a recess provided in the inner peripheral surface from near the rear end to the front, a through hole located in the recess and communicating with the outer peripheral surface of the front half, and a through hole communicating with the through hole of the front half. A groove provided on the outer circumference of the cut pin at a position where the ejector pin protrudes from the mold surface on the movable side of the molding space communicates with a recessed portion of the ejector pin to leak the air pressure to the mold surface. It is characterized by a configuration that

[Function] Since the ejector pin constitutes a movable mold plate surface, it is filled with molten resin to shape the clamping area, and a center hole is cut and formed by the cut pin.

When air pressure acts on the rear end of the piston, the ejector pin moves to the extended position. Along with this movement, the air pressure action chamber and the groove provided on the outer periphery of the cut pin come into communication, so this groove communicates with the recess of the ejector pin, and communicates with the front half whose diameter has been reduced through the through hole. A large amount of the air pressure is blown out from the groove in the movable mold surface toward the movable mold surface, leading to mold release.

[Example] The drawings show an example of the ejector pin of a mold for molding a disk-shaped recording medium according to the present invention, FIG. 1 is a perspective view of the same, and FIG. 2 is a mold for molding a disk-shaped recording medium using the same pin. FIG. 3 is an enlarged sectional view of the main part showing the pin in the standby state, and FIG. 4 is a sectional view of the main part showing the pin in the protruding state.

The ejector pin 1 has a cylindrical shape as a whole and consists of a large-diameter piston 11 provided at its rear end and a cylindrical body portion 12 in front of the piston 11. The piston 11 has a rear end surface 13 that serves as a working surface when protruding, and a front end surface 14 that serves as a working surface when returning.A sealing material 16 is provided in a groove 15 on the outer periphery of the piston 11. The body 12 has a recess 17 on its inner peripheral surface from near the front end surface 14 to just before the front end of the body, and the recess 17 has through holes 18 extending to the inner and outer peripheries.
is drilled. On the outer periphery of the body 12, a sealing material 19 is provided in the rear half, and the through holes 18 and grooves are provided in the front half 111, which is slightly reduced in diameter. These grooves, holes 18, and the recess 17 constitute an air passage. The groove is communicated with the circumferential grooves 112 and 113 and the axis groove 114,
The circumferential groove 113 is located on the protruding surface 115 at the tip, and the distance between the two is set to a stroke Xi that does not impair the flatness of the disk.

The operation of a disk-shaped recording medium molding die to which the ejector pin 1 is applied will be described in detail.

Thus, the mold comprises a fixed mold plate 2 and a movable mold plate 3 to form a cavity 4 having a disk molding space, a sprue bush 5 is attached to the fixed side in a cylindrical structure, and a cut pin 6 is opposed to the movable side. installed.

To explain in detail from the fixed side, the heald side and barrel side of the cylinder are made up of holes in the fixed receiving plate 21 and the fixed mounting plate 22, and the bottom side is made up of the bushing cylinder 51. The remaining space where the part fits into the hole is filled with the working chamber 2 of pressure oil.
It consists of 3. The above sprue bush 5 is
It is comprised of a large diameter part 52 mounted in the cylinder space and a small diameter part 53 extending from the large diameter part 52. The large diameter portion 52 is formed by a step portion 55 having a larger diameter than the spherical portion 54, and the step portion 55 is formed by the action chamber 2.
3 and receives pressure oil from the flow path 24. In the figure, 56 is a sprue hole, 57 . . . is a sealing material between each member, and 58 is a bolt for fixing the bush cylinder 51. Furthermore, the small diameter portion 5 of the sprue bush 5
3 is inserted into a hole in the fixed receiving plate 22 so as to be movable forward and backward, and its tip end surface 59 is normally aligned with the core surface of the cavity 4 and projected. Note that 25 is a refrigerant passage in the fixed mold plate 2.

The above-mentioned sprue bush 5 suppresses the nozzle touch force by applying pressure oil to the action chamber 23 in response to the high pressure generated when the cavity 3 is filled with molten resin. It adds

Next, to explain the movable side, the center of the cavity 4 has a sprue ejector pin 7 and a cut pin 6, and the ejector pin 1 is connected to the outer periphery of the cut pin 7 and the cylindrical member 3 in the clamping area of the finished product.
A stamper inner periphery pressing member 8 is movably inserted into the inner periphery of the cylindrical member 21, and a stamper inner periphery pressing member 8 is provided on the outer periphery of the cylindrical member 21 so as to be movable back and forth, and a stamper 41 and an outer periphery pressing member (not shown) are provided in the information track surface area. It consists of

The cutting pin 6 is composed of an elongated small diameter part 61 and a large diameter part 62, the large diameter part 62 is fitted inside the cutting pin cylinder 63 and the small diameter part 61 is fitted inside the ejector pin 1 so as to be movable in the forward and backward directions, and further, The rear end is fixed to an ejector plate (not shown). The small diameter portion 61 has the same cross section as the small diameter portion 53 of the sprue bush 5, and is arranged opposite to the small diameter portion 53 so as to be able to move forward and backward,
Its tip surface 64 protrudes beyond the movable mold surface of the cavity 4 and connects the gate 42 with the sprue tip surface 59.
is configured. Inside the cut pin 6, from the tip side, there is a slack well portion 65, a small hole 66, a communication hole 67 with a larger diameter than the small hole 66, and a cylinder 68 with an even larger diameter. A sprue ejector pin 7 is fitted so as to be movable forward and backward.
An end surface 69 of the large diameter portion 62 faces an unillustrated working chamber defined by the cut pin cylinder 63. Note that 161 is a refrigerant flow path provided in the large diameter portion 62, and 162 is a sealing material.

The cut pin 6 removes pressure oil from the action chamber 23 to advance the tip end surface 59 of the sprue bush 5 in a no-load or negative pressure state, and in synchronization with this forward force, retreats the tip end surface 59 with the same gate volume. The cut is made using the same method.

Ejector pin 1 related to the above cut pin 6
Explain the surroundings. A groove 163 is provided on the outer periphery of the small diameter portion 61 from near the rear end surface of the ejector pin 1 toward the tip side. configured. Groove 163
The rear end is closed by the pin inner circumferential surface at the stop position of the ejector pin 1, and the distance X2 from the pin rear end surface 13 is set to be slightly narrower than the stroke X1. In the figure, 116 and 117 are piston 1
A cylindrical member 31 and a cut pin cylinder 6 are installed before and after 1.
a working chamber divided by 3 and 118, 119;
are channels to the working chambers 116, 117.

The sprue ejector pin 7 consists of a pin-shaped protruding pin part 71, a blade-shaped flat part 72, and a large-diameter piston 73, respectively.
are fitted into each of the holes 66 to 68 of the cut pin 6. The flat portion 72 extends a blade portion 74 so as to vertically block the communication hole 67 along its length, and a reduced taper portion 75 is formed at the tip of the blade portion 74. The tapered portion 75 is
The inner wall of the communication hole 67 constitutes a communication passage. As a result, the passage blocked above and below the communication hole 67 communicates with the refrigerant flow paths 161, 161, and a circuit is configured in which the passage connects the tapered portion 75 in a divided state and is supplied. It happens. This circuit functions regardless of whether the sprue ejector pin 7 moves forward or backward. Also, the piston 73 is locked at its rear end and normally moves to follow the cut pin 6;
It can move independently by receiving a pressure medium in the cylinder hole 68. In the figure, 76 is a sealing material.

Only the effects unique to the present invention based on the above configuration will be explained.

When air is supplied from the flow path 118 to the action chamber 116 after the mold opening starts, it acts on the rear end surface 13, so that the protruding surface 115 of the ejector pin 1 protrudes from the mold surface. As the ejector pin 1 moves the distance X2, the groove 1
63 is exposed, some of the air flows into the groove 16.
3 into the recess 17, through hole 18, circumferential groove 112, shaft groove 114, and circumferential groove 113, which are passages. In this position, no air flows out from the mold surface.

Next, it is projected by a slight stroke X1 to reach the initial projected position. The initial ejection does not strongly release the product 43 from the mold surface;
Do not cause effects such as sledging.

As the stroke X1 moves, the circumferential groove 113 is exposed from the mold surface and opens in a ring shape. As a result, a portion of the air is blown out from the groove 163 through the passage from the circumferential groove 113 in the circumferential direction along the mold surface. In this case, since the ejector pin 1 protrudes from the clamping area of the finished product 43, air is blown out to the information track surface and enters between the stamper 41 and the information track surface, making it easy to release the mold. .

Further, the ejector pin 1 is projected, but since the information track surface has already been raised by the air, the mold can be released without damaging the unevenness. After ejection, the product is moved out of the mold by a product ejection mechanism or the like.

After the ejection is completed, air is removed from the action chamber 116 and at the same time air is supplied from the flow path 119 to the action chamber 117, so the ejector pin 1 retreats and returns to its original state.

According to the above embodiment, air is injected in a ring shape from the cylindrical protrusion surface 115 at the initial protrusion position, so that a mold release effect can be obtained over the entire disk. In particular, since the air is blown out at a position away from the protruding surface 115 by the stroke X1, the flatness of the disk is not impaired.

[Effects of the invention] As explained above, the invention provides the following effects.

The ejector pin includes a large diameter cylindrical piston provided at the rear end and a cylindrical body portion provided in front of the piston and having a reduced diameter front half,
This body has a recess provided in the inner peripheral surface from near the rear end to the front, a through hole located in the recess and communicating with the outer peripheral surface of the front half, and a through hole that communicates with the through hole and connects to the front half. The groove provided on the outer periphery of the cut pin at the position protruding from the movable mold surface communicates with the recess of the ejector pin, thereby leaking air pressure and causing the front half to Air could be injected from the groove, and disk curvature could be prevented. In particular, by forming an air chamber around the outer periphery of the front half, it is possible to prevent a drop in air pressure and perform powerful air injection.

It was possible to create an air blowing structure in which the cut pin was housed inside the ejector pin, and it could be put to practical use as a special ejector pin for disc molding that cuts the inside of the protruding position.

By forming an air chamber in the middle to leak air pressure, the structure and control system were simplified.

[Brief explanation of the drawing]

The drawings show an embodiment of the ejector pin of the mold for molding a disc-shaped recording medium according to the present invention, FIG. 1 is a perspective view of the same, and FIG. FIG. 3 is an enlarged sectional view of the main part showing the pin in a standby state, and FIG. 4 is a sectional view of the main part showing the pin in the protruding state. 1... Ejector pin, 2... Fixed template, 3...
...Movable template, 4...Cavity, 5...Sprue bush, 6...Cut pin, 7...Sprue ejector pin, 11...Piston, 12...Body, 1
7... Recessed portion on inner peripheral surface, 18... Through hole, 111...
...First half, 112, 113, 114... Circumferential groove, 1
15...Protruding surface, 163...Groove portion.

Claims (1)

[Scope of Claim for Utility Model Registration] In a mold for molding a disc-shaped recording medium that constitutes a disc-shaped molding space from a fixed mold plate and a movable mold plate, the outer periphery of a cut pin provided at the center of the movable mold plate side of the molding space. An ejector pin is fitted into the holder so that it can move forward and backward using air pressure. The body includes a recess provided in the inner peripheral surface from near the rear end to the front, a through hole located in the recess and communicating with the outer peripheral surface of the front half, and a through hole communicating with the through hole. A groove provided on the outer periphery of the cut pin at a position where the ejector pin protrudes from the movable die surface of the molding space is communicated with a recessed portion of the ejector pin, and a groove is provided toward the front of the outer circumferential surface of the front half part. An ejector pin for a mold for forming a disc-shaped recording medium, which is characterized by leakage to the mold surface.