JPH0623726U - Vacuum injection molding equipment - Google Patents

Abstract

(57) [Summary] [Objective] It is an object to provide an inexpensive vacuum injection molding apparatus having a simple structure, particularly a nozzle structure, and a small number of parts. A nozzle 10 for fitting a nozzle 10 of an injection molding machine into a mold 1 provided with a sprue 6 communicating with a cavity 3
Nozzle chamber 7 having a peripheral wall surface 8 parallel to the outer peripheral surface 14 of the
And the exhaust holes 19 and 20 communicating with the vacuum source are opened in the nozzle housing chamber 7, and when the nozzle 4 is fitted in the nozzle housing chamber 7, the nozzle housing chamber 7 is slidably contacted with the peripheral wall surface 8 of the nozzle housing chamber 7. An annular sealing material 12 that seals an annular gap between the nozzle accommodating chamber 7 and the nozzle 4 to form an airtight structure is attached to the outer peripheral surface 14 of the nozzle 4 or the peripheral wall surface 8 of the nozzle accommodating chamber 7 of the injection molding machine. However, the nozzle 4 is not provided with a complicated means for exhausting the gas, and the inside of the cavity 3 can be evacuated prior to the injection of the molding material with a simple nozzle structure without requiring a nozzle having a special structure.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an injection molding device for rubber products and plastic products. More specifically, the present invention relates to a vacuum injection molding apparatus that performs vacuum injection inside a cavity to perform injection molding.

[0002]

[Prior art]

 The air remaining in the cavity of the mold makes it difficult to completely fill the molding material into the cavity during injection molding of rubber products and plastic products. It may cause deterioration of physical or physical characteristics. Therefore, as a remedy for this, a vacuum injection molding apparatus that exhausts the inside of the cavity before injecting the molding material has been conventionally proposed.

As a conventional vacuum injection molding apparatus, for example, there is one disclosed in Japanese Utility Model Laid-Open No. 62-159612. This vacuum injection molding apparatus, as shown in FIG. 3, has a nozzle 101 of the injection molding machine, in addition to a hole 104 for injecting the molding material, an exhaust hole 105 for evacuation, and before injection of the molding material. The exhaust holes 105 are used to discharge the air in the cavities 108 of the molds 106 and 107. A bag sleeve 102 that can move in and out in the axial direction is attached to the tip of the nozzle 101, and is provided so as to be constantly pushed out by the force of a spring 103. The bag sleeve 102 faces the tip end surface 109 of the nozzle 101 before the tip end surface 109 of the nozzle 101 comes into contact with the nozzle seat surface 111 formed of a tapered recess in which the sprue 110 on the fixed mold 106 side is arranged. The airtight chamber 112 is formed by surrounding the nozzle sheet surface 111 of the fixed mold 106. The bag sleeve 102 has an elastic sealing material 113 from the front end surface to the inner peripheral surface thereof. It is provided so as to seal between the nozzle 102 and the nozzle 101 and between the bag sleeve 102 and the fixed mold 106. The bag sleeve 102 contacts the fixed mold 106 immediately before the nozzle 101 is pressed against the tapered nozzle seat surface 111, and the gap between the nozzle seat surface 111 and the nozzle tip surface 109 is sealed in the airtight chamber 112. As a result, the air in the cavity 108 can be evacuated by the exhaust hole 105 of the nozzle 101 through the airtight chamber 112 through the airtight chamber 112. After that, by further lowering the nozzle 101 and pressing it against the nozzle sheet surface 111, the exhaust hole 105 is closed by the nozzle sheet surface 111, and the injection hole 104 and the sprue 110 are connected to enable injection of the molding material. . At this time, the bag sleeve 102 compresses the spring 103 and relatively retracts, allowing the nozzle 101 to move.

[0004]

[Problems to be solved by the device]

 However, in this conventional vacuum injection molding apparatus, in addition to the hole 104 for injecting the molding material at the tip of the nozzle 101, the exhaust hole 105 is required, the bag sleeve 102 is movably mounted, and the spring 103 is used. In addition, since the bag sleeve 102 must be able to be brought into close contact with the fixed mold 106 by the elastic seal material 113, the nozzle structure is complicated and the number of parts is large, which is expensive. Further, since the bag sleeve 102 has to move while maintaining an airtight state for each injection molding, there are problems that the movement of the bag sleeve 102 is hindered and durability is poor.

An object of the present invention is to provide an inexpensive vacuum injection molding apparatus having a simple structure, particularly a nozzle structure, and a small number of parts.

[0006]

[Means for Solving the Problems]

 In order to achieve such an object, the present invention relates to a vacuum injection molding apparatus that performs vacuum injection in a cavity to perform injection molding, in which a nozzle of an injection molding machine is fitted to a mold provided with a sprue communicating with the cavity. A nozzle containing chamber having a peripheral wall surface parallel to the outer peripheral surface is formed, and an exhaust hole communicating with a vacuum source is opened in the nozzle containing chamber, so that when the nozzle is fitted into the nozzle containing chamber, An annular sealing material that makes sliding contact with the peripheral wall surface and seals the annular gap between the nozzle storage chamber and the nozzle to form an airtight structure is attached to the outer peripheral surface of the nozzle of the injection molding machine or the peripheral wall surface of the nozzle storage chamber. I am trying to do it.

[0007]

[Action]

 Therefore, when the nozzle of the injection molding machine is inserted into the nozzle housing chamber after the molding die is clamped and the annular sealing material is fitted to the peripheral wall surface of the nozzle housing chamber, the inside of the nozzle housing chamber is hermetically sealed by the nozzle. It becomes a structure. Therefore, when a vacuum is drawn through an exhaust hole that opens into the nozzle housing chamber, the nozzle housing chamber and the cavity communicating with the nozzle housing chamber are maintained in a depressurized state. After that, when the nozzle is lowered to bring the tip surface of the nozzle into contact with the bottom of the nozzle housing chamber, the exhaust hole is closed by the nozzle and the nozzle and the sprue are directly connected. The molten injection material is injected into the cavity.

[0008]

【Example】

 Hereinafter, the configuration of the present invention will be described in detail based on the embodiments shown in the drawings.

FIG. 1 shows an embodiment of the vacuum injection molding apparatus of the present invention. The molding die used in this apparatus is composed of at least two divisible molds, for example, a fixed mold 1 and a movable mold 2, and a cavity 3 corresponding to the shape of the molded product is formed on the divided surface. .

The fixed mold 1 is attached to, for example, a fixed plate 4 supported by a fixed die plate 15 and is provided with a pin gate 5 and a sprue 6 connected to the cavity 3 and a nozzle accommodating chamber 7 in which the sprue 6 is opened. Is formed. The nozzle accommodating chamber 7 is composed of a concave portion that fits the tip portion of the nozzle 9 in a completely accommodated state, and has a peripheral wall surface 8 parallel to the outer peripheral surface 14 of the nozzle 10 and a bottom 9 that contacts the tip surface 18 of the nozzle 10. have. That is, the nozzle accommodating chamber 7 is composed of a concave portion having a similar shape slightly larger than the outer shape of the nozzle 10. Further, at the center of the bottom 9 of the nozzle accommodating chamber 7, there is opened an exhaust hole 20 which communicates with a vacuum source (not shown) through an exhaust hole 19 on the movable mold 2 side during mold clamping. A nozzle insertion hole 17 is formed in the fixed plate 4 and the fixed die plate 15.

The movable mold 2 is fixed to, for example, a movable plate 16 that is movable up and down, and a cylinder (not shown) connected to the movable plate 16 drives the movable mold 2 to move it relative to the fixed mold 1. It is slidably supported by, for example, rods 21 and 21 so as to approach or separate. An exhaust hole 19 communicating with a vacuum source (not shown) is coaxially opened in the movable mold 2 so as to coincide with the exhaust hole 20 of the fixed mold 1. The exhaust hole 19 is connected to a vacuum source (not shown) by, for example, piping.

The nozzle 10 of the injection molding machine has a hole 13 for injecting a molding material. An annular groove 11 is formed on the outer peripheral surface 14 of the nozzle 10 near the tip side, and an annular seal material 12 is fitted in the groove 11. The ring-shaped sealing material 12 is not particularly limited, but an O-ring is generally used, for example. Here, before the nozzle 10 is fitted into the nozzle housing chamber 7 in the fixed mold 1 and the nozzle tip portion 18 abuts the bottom 9 of the nozzle housing chamber 7 of the fixed mold 1, the O-ring 12 is It is provided at a position capable of forming an airtight chamber communicating with the cavity 3 through the sprue 6 pin gate 5 between the stationary mold 1 and the peripheral wall surface 8 of the nozzle housing chamber 7.

With the above-described configuration, after the fixed mold 1 and the movable mold 2 are clamped, the nozzle 10 may be moved toward the fixed mold 1 by a driving device (not shown). The tip of the nozzle 10 is fitted into the nozzle housing chamber of the fixed mold 1 and the O-ring 12 is brought into sliding contact with the peripheral wall surface 8 of the nozzle housing 7 so that the space between the fixed mold 1 and the tip portion 18 of the nozzle 10 is fixed. To form an airtight chamber. When the movement of the nozzle 10 is stopped in this state and the exhaust hole 19 is evacuated by a vacuum pump or the like, the residual air in the cavity 3 is exhausted from the pin gate 5 and the spool 6 through the airtight nozzle accommodating chamber 7.

After the inside of the cavity 3 has been depressurized to a predetermined pressure and evacuated, the nozzle 10 is lowered again to bring the nozzle tip 18 into contact with the bottom 9 of the nozzle housing chamber 7 of the fixed mold 1. At this time, the exhaust hole 19 is closed by the nozzle tip portion 18 in an airtight state. When the molding material is injected from the nozzle 10 in this state, the molding material is injected into the cavity 3 through the injection hole 13, the sprue 6 and the pin gate 5.

It should be noted that the above-described embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention. For example, as shown in FIG. 2, the exhaust port 19 may penetrate only the fixed mold 1 and be opened directly on the peripheral wall surface 8 of the nozzle storage chamber 7. Although not shown in the drawings, the installation of the sealing material 12 on the nozzle 4 side may be omitted by disposing an annular sealing material such as an O-ring on the peripheral wall surface 8 side of the nozzle storage chamber 7. .

[0016]

[Effect of device]

 As is clear from the above description, the vacuum injection molding apparatus of the present invention is a nozzle having a peripheral wall surface parallel to the outer peripheral surface of the nozzle for fitting the nozzle of the injection molding machine into the mold provided with the sprue communicating with the cavity. An exhaust hole communicating with a vacuum source is formed in the nozzle accommodating chamber while forming the accommodating chamber, and when the nozzle is fitted into the nozzle accommodating chamber, the nozzle accommodating chamber is slidably in contact with the peripheral wall surface of the nozzle accommodating chamber and the nozzle accommodating chamber. Since an annular seal material that seals the annular gap between the nozzle and the outer peripheral surface of the nozzle of the injection molding machine or the peripheral wall surface of the nozzle housing chamber is installed, a complicated means for exhausting the nozzle is provided. There is no provision, and the nozzle structure is simple. That is, a nozzle having a special structure is not required, and it suffices to provide a groove for fitting an O-ring on the outer peripheral surface of a conventional general nozzle.

Further, the structure on the die side may be a simple structure in which a nozzle accommodating chamber having a shape similar to the nozzle shape is formed and an exhaust hole is provided for communicating this with a vacuum source. Therefore, the device can be manufactured at low cost.

Further, since the present invention has a simple structure, the exhaust path including the airtight chamber can be made extremely small, so that the exhaust time can be shortened and efficient molding work can be performed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a schematic structure of a vacuum injection molding apparatus of the present invention.

FIG. 2 is an enlarged view of an essential part showing another embodiment of the vacuum injection molding apparatus of the present invention.

FIG. 3 is a cross-sectional view of a main part of a conventional vacuum injection molding device.

[Explanation of symbols]

 1 Fixed Side Mold 2 Moving Side Mold 3 Cavity 10 Nozzle 7 Nozzle Storage Chamber 8 Nozzle Storage Chamber Perimeter Wall 9 Nozzle Storage Chamber Bottom 11 Annular Groove 12 Annular Sealing Material 14 Nozzle Outer Surface

Claims (1)

[Scope of utility model registration request] 1. A vacuum injection molding apparatus for performing vacuum injection molding in a cavity, in which a nozzle of an injection molding machine is fitted in a mold provided with a sprue communicating with the cavity and is parallel to an outer peripheral surface of the nozzle. A nozzle accommodating chamber having a peripheral wall surface is formed, an exhaust hole communicating with a vacuum source is opened in the nozzle accommodating chamber, and when the nozzle is fitted into the nozzle accommodating chamber, the nozzle accommodating chamber slides on the peripheral wall surface of the nozzle accommodating chamber. A ring-shaped sealing material that is in contact with and seals an annular gap between the nozzle housing chamber and the nozzle to form an airtight structure is attached to the outer peripheral surface of the nozzle of the injection molding machine or the peripheral wall surface of the nozzle housing chamber. Characteristic vacuum injection molding equipment.