JP5912818B2 - Resin casting mold - Google Patents

Description

  Embodiments of the present invention relate to a resin casting mold that can suppress voids formed in a resin casting product.

  In high voltage devices such as switch gears, resin casting products obtained by filling a resin casting mold with a thermosetting resin such as an epoxy resin and heat-curing the resin are often used. Resin cast products are required to have excellent electrical and mechanical properties.

  Conventionally, a resin casting mold used in the pressure gelation method has a cavity for obtaining a resin casting product of a predetermined shape, and is filled with epoxy resin from an injection runner provided at the bottom. The The epoxy resin is depressurized and defoamed, and then kept at a low temperature of 40 to 70 ° C. to ensure pot life, and is injected under pressure into a resin casting mold set at a high temperature of 120 to 150 ° C. A slit-like exhaust groove connected to the outside air and a resin reservoir connected to the exhaust groove are provided on the cavity upper portion of the mating surface of the resin casting mold. Thereby, in the cavity, residual air is pushed out from the exhaust groove by filling with epoxy resin to prevent formation of voids (see, for example, Patent Document 1).

  However, depending on the shape of the cavity, residual air may not necessarily be exhausted from the exhaust groove. In particular, when a flat surface was provided on the upper surface of the cavity, a small amount of residual air was likely to remain in this portion in the form of bubbles. This becomes a void and deteriorates the electrical and mechanical properties of the resin cast product.

JP 2011-25530 A

  The problem to be solved by the present invention is to provide a resin casting mold that can efficiently exhaust residual air that tends to remain on the upper surface of the cavity from the exhaust groove and prevent formation of voids. .

In order to solve the above problems, a resin casting mold according to an embodiment includes a mold, a nest inserted in the mold, a cavity carved in a mold mating surface of the mold, and the cavity. an injection liner for injecting a thermosetting resin into said injection facing the liner and an exhaust groove provided in the resin ultimate surface within said cavity to divide the nested plurality, at least the mold alignment wherein the surface, the fitting surface of the nest and the mold, and the exhaust groove provided Rutotomoni between the nest, in that the exhaust groove between the nest provided in a direction perpendicular to the mold mating surface And

1 is a half cross-sectional view showing a configuration of a resin casting mold according to Example 1 of the present invention. The top view which shows the structure of the resin casting mold which concerns on Example 1 of this invention. The top view which shows the structure of the resin casting die which concerns on Example 2 of this invention. The principal part half sectional view which shows the structure of the resin casting mold which concerns on Example 3 of this invention. The principal part half sectional view which shows the structure of the resin casting mold which concerns on Example 4 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a resin casting mold according to Example 1 of the present invention will be described with reference to FIGS. FIG. 1 is a half sectional view showing the configuration of a resin casting mold according to the first embodiment of the present invention, and FIG. 2 is a top view showing the configuration of the resin casting mold according to the first embodiment of the present invention. .

  As shown in FIG. 1, the resin casting mold is composed of a first mold 1 and a second mold 2 with the mold mating surface of the intermediate portion shown in the figure as a boundary. Since the first mold 1 and the second mold 2 are symmetrically arranged and have the same configuration, the following description will be made using the first mold 1.

  The first mold 1 is provided with a first nest 3 that is divided into a main body mold and is fitted into the main body mold. The first mold 1 and the first nest 3 are used for the first mold 1. A mold mating surface for mating the mold 1 and the second mold 2 is formed. A cavity 4 having a predetermined shape is engraved in the center of the mold mating surface. The shape of the cavity 4 is roughly divided into a top surface portion 4a formed by the first insert 3 portion, a side surface portion 4b formed by the first mold 1, and a bottom surface portion 4c.

  An injection liner 5 having a semicircular cross section is provided on the die mating surface of the bottom surface portion 4c and connected to the outside. In the upper surface portion 4a, a slit-like first exhaust groove 6 is provided in the first insert 3 serving as a mold mating surface, and is connected to the outside air. A first resin reservoir 7 having a semicircular cross section is provided at an intermediate portion of the first exhaust groove 6. A slit-like second exhaust groove 8 is also provided on the fitting surface between the first insert 3 and the first mold 1 and is connected to the outside air. In the middle part of the second exhaust groove 8, a second resin reservoir 9 having a semicircular cross section is provided in each of the first insert 3 and the first mold 1. The first and second exhaust grooves 6 and 8 have a depth of several hundred μm. The radius which becomes the depth of the first and second resin reservoirs 7 and 9 is larger than that of the first and second exhaust grooves 6 and 8.

  The range in which the first and second exhaust grooves 6 and 8 are provided is shown in FIG. 2, and covers the entire upper surface portion 4 a of the cavity 4. In particular, the second exhaust groove 8 is provided on the flat surface of the upper surface portion 4a which is the back of the cavity 4 connected to the corner, avoiding the corner portion of the cavity 4.

  Thereby, when the epoxy resin is injected from the injection liner 5 and the inside of the cavity 4 is filled from the lower part to the upper part, the residual air is exhausted from the first and second exhaust grooves 6 and 8, and the upper surface part Exhaust even a very small amount of residual air trying to stay at 4a. When the epoxy resin reaches the upper surface portion 4a and flows into the first and second exhaust grooves 6, 8, the width is thin, so that the epoxy resin hardens faster than inside the cavity 4, and the flow of the epoxy resin stops. The inside of 4 is pressurized. When the predetermined pressure is reached and heat curing proceeds, a voidless resin cast can be obtained. The burrs hardened in the first and second exhaust grooves 6 and 8 are removed.

  Here, since the epoxy resin filled in the cavity 4 is filled in the first and second exhaust grooves 6 and 8 after the upper surface 4a is filled, the upper surface 4a is filled in the cavity 4. This is referred to as the final resin surface.

  The first and second resin reservoirs 7 and 9 increase the flow rate of the epoxy resin in the first and second exhaust grooves 6 and 8 before curing, and promote exhaust of residual air. If it can be efficiently exhausted, it can be omitted. If the first and second resin reservoirs 7 and 9 are provided closer to the cavity 4, the exhaust efficiency of residual air can be improved. The first exhaust groove 6 is formed between the first insert 3 of the first mold 1 and the insert of the second mold 2, but is simply referred to as being formed on the mold mating surface. In addition, the 1st exhaust groove 6 and the 1st resin reservoir 7 correspond to the prior art provided in the die-mating surface without a nesting.

  According to the resin casting mold of the first embodiment, the upper surface portion 4a of the cavity 4 is the nest 3 and the exhaust groove 6 and the first groove 1 are formed on the mold mating surfaces of the first and second molds 1 and 2. Since the exhaust groove 8 is provided on the fitting surface between the mold 1 and the insert 3, a small amount of residual air that is easily moored on the upper surface portion 4a can be efficiently exhausted, and a voidless resin cast product can be obtained. it can.

  Next, a resin casting mold according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is a top view showing the configuration of the resin casting mold according to the second embodiment of the present invention. The second embodiment is different from the first embodiment in that the nesting is divided. In FIG. 3, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, the first mold 1 is fitted with second and third inserts 10 and 11 that are divided in the horizontal direction in the figure. The fitting surface between the third exhaust groove 12 and the resin reservoir 13 and the second and third inserts 10 and 11 is formed on the die mating surface, and the fourth exhaust groove 14 and the resin reservoir 15 are formed on the fitting surface between the second and third inserts 10 and 11. A fifth exhaust groove 16 and a resin reservoir 17 are provided on the fitting surfaces of the inserts 10 and 11 and the first mold 1.

  According to the resin casting mold of the second embodiment, in addition to the effects of the first embodiment, the upper surface portion 4a of the cavity 4 is divided into a plurality of inserts 10 and 11, so that the exhaust efficiency can be improved. it can.

  Next, a resin casting mold according to Example 3 of the present invention will be described with reference to FIG. FIG. 4 is a half sectional view of an essential part showing the configuration of the resin casting mold according to the third embodiment of the present invention. The third embodiment is different from the second embodiment in the shape of the exhaust groove. In FIG. 4, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, the fourth exhaust groove 14 is provided with a step that is wide on the cavity 4 side and narrow on the outside, and the inclined portion extends outward from the center of the mold. 18 and so on. That is, it has an inclination extending toward the adjacent exhaust grooves 12 and 16.

  According to the resin casting mold of the third embodiment, in addition to the effect of the second embodiment, the residual air in the fourth exhaust groove 14 is easily moved by the inclined portion 18, resulting in the inside of the cavity 4. The exhaust efficiency of residual air can be improved.

  Next, a resin casting mold according to Example 4 of the present invention will be described with reference to FIG. FIG. 5 is a half sectional view of the main part showing the configuration of a resin casting mold according to Example 4 of the present invention. The difference between the fourth embodiment and the second embodiment is the shape of the cavity. In FIG. 5, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 5, corners 4 d 1 and 4 d 2 are provided on the upper surface 4 a of the cavity 4. The corners 4 d 1 and 4 d 2 are divided into fourth and fifth nestings 19 and 20. Has been. The corner 4d1 of the fitting surface between the fourth and fifth inserts 19 and 20 has a corner of the fitting surface of the sixth exhaust groove 21 and the resin reservoir 22, and the fitting surface of the fifth insert 20 and the first mold 1. The part 4d2 is provided with a seventh exhaust groove 23 and a resin reservoir 24.

  Here, since the corner portions 4d1 and 4d2 are filled with the epoxy resin before the epoxy resin flows into the exhaust grooves 21 and 23, the upper surface 4a having the corner portions 4d1 and 4d2 reaches the final resin within the cavity 4. It is called a surface.

  According to the resin casting mold of Example 4 described above, a small amount of residual air tends to accumulate in the corners 4d1, 4d2, but the corners 4d1, 4d2 are divided by the nestings 19 and 20 and the exhaust grooves 21, 23 are separated. Thus, the exhaust efficiency of residual air can be improved.

  According to the embodiment as described above, the upper surface portion of the cavity facing the injection runner is divided by a plurality of inserts, and the exhaust groove is formed in each of the mold mating surface with the mold and the fitting surface between the inserts. Therefore, a small amount of residual air can be exhausted from these exhaust grooves, and a voidless resin cast product can be obtained.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1, 2 Molds 3, 10, 11, 19, 20 Nest 4 Cavity 4a Top surface 4b Side surface 4c Bottom surface 4d1, 4d2 Corner 5 Injection liner 6, 8, 12, 14, 16, 21, 23 Exhaust groove 7, 9, 13, 15, 17, 22, 24 Resin reservoir 18 Inclined portion

Claims (3)

Mold,
A nest that fits into the mold;
A cavity carved in the mold mating surface of the mold,
An injection liner for injecting a thermosetting resin into the cavity;
An exhaust groove provided on a resin final surface in the cavity facing the injection liner,
Dividing the nesting into a plurality,
At least the mold mating surface, the mating surface of the nest and the mold, and the exhaust groove provided Rutotomoni between the nest,
A resin casting mold , wherein the exhaust groove between the inserts is provided in a direction orthogonal to the mold mating surface . The width of the exhaust groove is wider on the cavity side than the outside of the mold, and the exhaust groove on the cavity side is an inclined portion having a step extending outward from the mold center. The resin casting mold according to claim 1. The resin casting mold according to claim 1 or 2, wherein a corner portion is formed on the final surface of the resin, and the insert is divided with the corner portion as a boundary .

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