JPH0735016U - Injection mold - Google Patents

Abstract

(57) [Summary] [Purpose] The molding cycle is reduced by reducing the manufacturing cost of the mold, facilitating maintenance / inspection and repair, and cooling the upper part of the movable core part of the core part. To shorten
(EN) Provided is an injection molding die capable of improving productivity. A movable core part 2 for molding the inner surface of a tubular body 1 is a partial core 2a for molding a part of the inner surface of the tubular body 1.
And an remainder core 2b for molding the inner surface of the remainder, which is provided separately, and the partial core 2a and the remainder core 2b are attached by a mounting bolt 5 to be integrated with each other.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 TECHNICAL FIELD The present invention relates to an injection molding die for molding a cylindrical body made of a synthetic resin having different sectional shapes in a part and the rest.

[0002]

[Prior art]

 Conventionally, in an injection molding die that molds a cylindrical body made of synthetic resin whose cross-sectional shape is different in part and in the rest, the movable core part for molding the inner surface side of the cylindrical body is integrally manufactured. What has been done is generally used. The structure of the above conventional injection mold will be described below with reference to the drawings.

FIG. 2 is a cross-sectional view showing an example of a conventional cylindrical injection-molding die in which a part of the cross-sectional shape is different from the rest, and an injection-molding die for a rain gutter made of hard vinyl chloride resin. It is a type. In FIG. 2, 10 is a tubular body (rain gutter top), 11 is a part of the tubular body 1, and 12 is the rest. The part 11 has a substantially circular cross-sectional shape, and one of the parts 11 gradually expands in cross section toward the remaining part 12 and is connected to the remaining part 12 (square shape). Reference numeral 20 denotes a core portion, which is used to form the inner surface of the cavity of the cylindrical body 10 and is integrally manufactured.

Reference numeral 30 is a fixed die, and 31 is a fixed die plate having a slide core (not shown). The fixed mold plate 31 is provided with a nest 32, and a sprue bush 33 is press-fitted into the center of the nest 32, and a sprue 40 and a runner 41 through which molten resin is injected are provided so as to penetrate therethrough.

Reference numeral 42 denotes a tunnel gate. The tunnel gate 42 is provided so as to be introduced from the upper end surface of the core portion 20 to the side surface of the cavity for molding the cylindrical portion 12. It is designed so that it is entirely filled and molded.

Since the tunnel gate 42 provided in the core portion 20 is subjected to a large shearing resistance due to its structure and is therefore subject to severe wear, and has the shortest service life, daily maintenance and inspection may be neglected during continuous use. Can not.

[0007]

[Problems to be solved by the device]

 However, in the case of the above-mentioned tubular body injection molding die, a large machine tool is required for manufacturing the core portion 20, a large machine tool is required, the processing cost is high, and repair is bulky. It has to be removed from the movable template, which requires a lot of man-hours. Further, when the remaining portion 12 of the core portion 20 is heavily worn and cannot be restored by repairing, there is a problem that it is necessary to newly remake the entire core portion 20.

The present invention has been made by paying attention to the above-mentioned problems, and solves these problems, reduces the manufacturing cost of the mold, and facilitates maintenance / inspection and repair. Further, by providing a structure in which the upper part of the movable die core can be cooled, the injection cycle die can be provided which can shorten the molding cycle and improve the productivity.

[0009]

[Means for Solving the Problems]

 The injection mold of the present invention is an injection mold composed of a fixed mold and a movable mold for molding a cylindrical body made of synthetic resin having different sectional shapes in part and the rest. The movable core part for molding the inner surface side of the body is divided into a partial core for molding the inner surface of a part of the tubular body and a remaining core for molding the inner surface of the remaining part. It is characterized in that the core part and the remaining core part are attached together by mounting bolts.

[0010]

[Action]

 In the injection molding die of the present invention, the core part of the movable die for molding the inner surface side of the tubular body has a partial core for molding a part of the inner surface of the tubular body and a remaining portion for molding the inner surface of the remaining portion. The core is divided into two parts, and the partial core and the remaining core are attached by the mounting bolts to form a unit, which reduces the manufacturing cost of the mold and facilitates maintenance, inspection and repair. The remaining core can have a structure that can be cooled, the molding cycle can be shortened, and the productivity can be improved.

[0011]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the injection mold of the present invention, which is an injection mold for a rain gutter made of hard vinyl chloride resin. In FIG. 1, 1 is a tubular body (rain gutter top), 1a is a part of the tubular body 1, and 1b is the rest. This part 1a has a substantially circular cross-sectional shape, and one of the parts 1a gradually expands in cross section toward the remaining part 1a and is connected to the remaining part 1b (square shape).

Reference numeral 2 denotes a movable core part, and the core part 2 includes a partial core 2a for molding the inner surface of the cavity of the part 1a and a remaining core for molding the inner surface of the cavity of the remaining part 1b. 2b is provided separately, and is attached by a mounting bolt 5 to be integrated. Reference numeral 6 denotes a cooling hole provided below the partial core 2a. By providing the cooling hole 6, the cooling effect of the partial core 2a after injection of the molten resin can be improved.

Reference numeral 3 is a fixed die, and 3a is a fixed die plate having a slide core (not shown). The fixed mold plate 3a is provided with a nest 3b, a sprue bush 3c is press-fitted in the center of the nest 3b, and a sprue 4 and a runner 4a through which molten resin is ejected penetrate through the center of the sprue bush 3c. It is provided.

Reference numeral 4b denotes a tunnel gate, and the tunnel gate 4b is provided so as to penetrate from the upper end surface of a part of the core 2a to the side surface of the cavity for molding the part 1a of the tubular body 1. Molten resin is filled into the entire cavity from the gate 4b and is molded.

As described above, in the injection mold of the present invention, the partial core 2a on the inner surface of the cavity for molding the part 1a of the tubular body 1 is divided from the lower residual core 2b. Since it is provided as an integral part and is attached by the mounting bolt 5, it can be easily assembled and disassembled.

Furthermore, a cooling hole 6 which could not be formed in the conventional structure can be newly provided, and as a result of an injection molding test using a hard vinyl chloride resin, at a molding cycle of 30 seconds, in the case of a conventional injection molding die, The temperature of the remaining core 2b was 50 degrees Celsius in the highest portion, but could be lowered to 42 degrees Celsius.

[0017]

[Effect of device]

 In the injection molding die of the present invention, the core part of the movable die for molding the inner surface side of the tubular body has a partial core for molding a part of the inner surface of the tubular body and a remaining portion for molding the inner surface of the remaining portion. The core is divided into two parts, and the partial core and the remaining core are attached by the mounting bolts to form a unit, which reduces the manufacturing cost of the mold and facilitates maintenance, inspection and repair. The remaining core can have a structure that can be cooled, the molding cycle can be shortened, and the productivity can be improved. Therefore, it is suitable as an injection molding die for molding a cylindrical body made of synthetic resin having different sectional shapes in part and in the rest.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an injection molding die of the present invention.

FIG. 2 is a cross-sectional view showing an example of a conventional cylindrical injection molding die.

[Explanation of symbols]

 1 Cylindrical Body 1a Part 1b Remaining 2 Core Part 2a Part Core 2b Remaining Core 3 Fixed Type 4 Sprue 31 Undercut Part

Claims (1)

[Scope of utility model registration request] 1. An injection molding die comprising a fixed mold and a movable mold for molding a synthetic resin tubular body having a different sectional shape in a part and the rest, wherein an inner surface side of the tubular body is molded. The movable core part for dividing the cylindrical body is divided into a partial core that molds the inner surface of a part of the tubular body and a residual core that molds the inner surface of the remaining part. An injection mold that is attached by bolts and is integrated.