Resin molding mold

Abstract

To reduce a risk of water leakage outside a resin molding mold due to compression set occurring in an O-ring over long-term use, which hinders sufficient reaction force, when an insert of the resin molding mold, which has a sprue bush with a cooling water passage, is assembled into a fixed mold and the O-ring is used for sealing off water at a water-stopping part at a boundary between the fixed mold and the insert.SOLUTION: A resin molding mold includes: a piston engagement pin that is fixed in a hole formed in the mold and has a temperature control piping formed inside; an elastic member inserted into the piston engagement pin and disposed within the hole; a piston fitted into the piston engagement pin and engaged with the elastic member, and being movable in a longitudinal direction of the piston engagement pin; and a fixing member that fixes the piston so as to be housed in the hole against an elastic force of the elastic member. When connected to a flow path of another mold, the piston is advanced into the other mold by releasing fixation of the fixing member, and the elastic force of the elastic member causes a tip of the piston to press against a periphery of the flow path of the other mold, thereby stopping water.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a mold for resin molding. [Background technology]

[0002] Injection molding is a well-known method for molding plastic parts using thermoplastic resins. To efficiently mold plastic parts using this injection molding method, it is necessary to shorten the time required for the series of molding processes (hereinafter referred to as cycle time), which consists of steps such as injecting the molten resin, holding pressure, cooling, measuring, opening and closing the mold, and ejecting the plastic part.

[0003] Although it is difficult to generalize as it depends on factors such as the shape and size of the resin part, the resin used, and the required quality, the cooling process is the step that takes the most time in this cycle. In the cooling process, the resin that has been heated to a high temperature and melted inside the injection unit is cooled and solidified by heat exchange when it comes into contact with the surface of the mold, which is adjusted to a temperature of 30 to 150°C by a mold temperature regulator. This cooling process is essential for removing the resin part from the mold with the shape engraved into it still transferred.

[0004] For example, the sprue, the part that high-temperature molten resin passes through first when it is injected into the mold, is one of the parts that particularly requires efficient cooling. From the moment the molten resin flows into the sprue, heat exchange begins with the mold surface, and over time, it cools and solidifies. If this sprue completely solidifies, the molten resin will not be able to fill the runner, gate, and product area where the shape of the resin part is engraved, which can cause various molding defects such as short circuits or sink marks.

[0005] For this reason, the sprue section is generally designed to have a larger cross-sectional area of ​​the resin flow path than other sections such as the runner section, and as a result, it often becomes the rate-limiting section of the cooling time where cooling and solidification are completed last in the mold. Therefore, in order to shorten the cycle time and improve the productivity of resin parts, a method of shortening the cooling time of the sprue section is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-218735 Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, a cooling water passage is provided on the outside of the sprue bush, and the resin in the sprue section is cooled by the cooling water flowing through this passage. This configuration promotes the cooling and solidification of the resin in the sprue section, which is expected to shorten the cycle time. When a resin molding die insert having a sprue bush with a cooling water passage is assembled into a fixed die, an O-ring is used in the watertight section at the interface between the fixed die and the insert. However, long-term use causes permanent compression set in the O-ring, which prevents sufficient reaction force from being obtained, increasing the risk of water leakage outside the die.

[0008] Furthermore, water cannot be completely prevented from entering the watertight section, and a small amount of water does enter. Water convection is difficult in this section, and the supply of oxygen dissolved in the water is stopped. As a result, a local cell is formed between the temperature control flow path and the section due to the difference in oxygen concentration. As a result, crevice corrosion occurs at the insert interface, creating gaps that lead to a decrease in watertightness.

[0009] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a resin molding mold having temperature control piping that can suppress a decrease in watertightness even during long-term use and can maintain the required cooling efficiency for a long period of time. [Means for solving the problem]

[0010] The resin molding mold disclosed herein has a water-stopping mechanism for connecting to a flow path of a temperature-control medium formed in another mold, and this water-stopping mechanism comprises a piston mating pin fixed to a hole formed in the mold and having a temperature-control piping formed inside it, an elastic member inserted into the piston mating pin and positioned within the hole, a piston mated to the piston mating pin and engaging with the elastic member and movable in the longitudinal direction of the piston mating pin, and a fixing member that fixes the piston so that it is stored in the hole against the elastic force of the elastic member, and is characterized in that when connecting to a flow path of another mold, the piston is advanced into the other mold by releasing the fixing member, and the elastic force of the elastic member causes the tip of the piston to press against the periphery of the flow path of the other mold to stop the water. [Effects of the Invention]

[0011] According to the resin molding mold of the present disclosure, the piston is pressed firmly against the water-stopping surface by the reaction force of the elastic member, thereby suppressing deterioration of water-stopping properties over long-term use and maintaining water-stopping performance for a long period of time. [Brief explanation of the drawings]

[0012] [Figure 1] 3 is a cross-sectional schematic view of the temperature adjusting water shutoff mechanism of the resin molding die according to the first embodiment when the piston moves forward. FIG. [Figure 2] 3 is a schematic diagram showing details of a piston of the resin molding die according to the first embodiment. FIG. [Figure 3] FIG. 3 is an assembly workflow diagram of the resin molding die according to the first embodiment. [Figure 4] 3 is a cross-sectional schematic view of the temperature adjusting water shutoff mechanism of the resin molding die according to the first embodiment when the piston is retracted. FIG. [Figure 5] 10 is a cross-sectional view showing a temperature adjusting water shutoff mechanism of a resin molding die according to a second embodiment when the piston is retracted. FIG. [Figure 6] 10 is a cross-sectional schematic view of the temperature adjusting water shutoff mechanism of the resin molding die according to the second embodiment when the piston moves forward. FIG. [Figure 7] FIG. 11 is a cross-sectional view showing a temperature adjusting water shutoff mechanism of a resin molding die according to a third embodiment when the piston is retracted. [Figure 8] 11 is a cross-sectional schematic view of a temperature adjusting water shutoff mechanism of a resin molding die according to embodiment 3 when the piston is moving forward. FIG. [Figure 9] FIG. 10 is a cross-sectional schematic view of the temperature adjusting water shutoff mechanism of the resin molding die according to the fourth embodiment when the piston is retracted. [Figure 10] 10 is a cross-sectional schematic view of a temperature adjusting water shutoff mechanism of a resin molding die according to embodiment 4 when the piston is moving forward. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, preferred embodiments of a resin molding die according to the present disclosure will be described with reference to the drawings. Note that the same reference numerals are used to designate the same contents and corresponding parts, and detailed descriptions thereof will be omitted.

[0014] Embodiment 1 Figure 1 is a cross-sectional schematic diagram of a temperature-controlling water-stop mechanism for a resin molding die according to embodiment 1 when the piston moves forward. The seal structure for a resin molding die having a temperature-controlling pipe can be placed anywhere in the resin molding die, but as mentioned above, improving the cooling efficiency of the sprue section leads to improved productivity of resin parts. Therefore, as an example, a sprue bushing insert having a temperature-controlling pipe will be described. Note that although this is a cross-sectional view, some hatching, such as for elastic members, has been omitted to simplify the explanation.

[0015] 1 is mainly composed of a sprue bushing insert 1, a temperature control flow path 2, a sprue portion 3, a fixed mold 10, a piston fitting pin 11, a spring and piston holding portion (hereinafter referred to as the spring / piston holding portion) 12, an elastic member 13, a piston 14, a positioning lock hole 15, and a positioning lock pin 16. The piston fitting pin 11, the elastic member 13, and the piston 14 are inserted into holes machined in the fixed mold 10.

[0016] The resin molding die 100 can be linked to the operation of an injection molding machine (not shown) by fixing the fixed die 10 and the movable die (not shown) in contact with the platen of the injection molding machine. A sprue bushing insert 1 is incorporated into the fixed die 10. The sprue bushing insert 1 is attached to introduce resin heated and melted by a heating barrel of the injection molding machine (not shown) into the resin molding die 100, and a sprue portion 3, which is a flow path for the molten resin, is provided inside the sprue bushing insert 1.

[0017] The sprue section 3 is machined with a temperature-controlling flow path 2 for efficiently cooling the molten resin that flows into the sprue section 3. A temperature-controlling medium introduced from a mold temperature regulator flows through the temperature-controlling flow path 2, allowing heat exchange with the molten resin that flows into the sprue section 3, thereby efficiently cooling the molten resin. The temperature-controlling flow path 2 may be a connected series of linear flow paths, or it may have a three-dimensional structure, such as the spiral shape shown in perspective in Figure 1. To efficiently cool the molten resin in the sprue section 3, it is preferable to arrange a large flow of temperature-controlling medium along the resin flow path in the sprue section 3. In addition, methods for machining a three-dimensional temperature-controlling flow path 2 include manufacturing it by layering metal material using a metal 3D printer, or by integrating multiple nested blocks of temperature-controlling flow path 2 using methods such as thermal diffusion bonding to manufacture a continuous temperature-controlling flow path 2.

[0018] A temperature control water stop mechanism consisting of a piston fitting pin 11, a spring / piston holding portion 12, an elastic member 13, a piston 14, a positioning lock hole 15, and a positioning lock pin 16 is incorporated into the fixed mold 10. The piston fitting pin 11 is cylindrical and has at least three different diameters. A hollow temperature control channel 2 is machined in the center of the cylinder's axis, through which a temperature control medium supplied from a temperature controller flows. The large-diameter section 11A, which has the largest diameter, has one end flush with one surface of the resin molding die 100. The piston fitting pin 11 is positioned by screwing it into the resin molding die 100 with a hexagon socket head bolt or the like. The small-diameter section 11C of the piston fitting pin 11 forms the spring / piston retaining section 12. An elastic member 13, whose diameter is larger than the diameter of the spring / piston retaining section 12, is inserted into the spring / piston retaining section 12, and a piston 14 is fitted into the small-diameter section 11C. The piston 14 is movable longitudinally along the spring / piston retaining section 12 of the piston fitting pin 11. One end of the elastic member 13 contacts the medium-diameter section 11B of the piston fitting pin 11, and the other end of the elastic member 13 is positioned so as to contact the piston 14.

[0019] In this embodiment, the elastic member 13 is described as a spring, but may be any other member having elastic force. Hereinafter, the elastic member 13 will be described as the spring 13. The spring 13 is disposed so as to be sandwiched between one end of the medium diameter portion 11B and the piston 14, and when pressed from the piston 14 side, the dimensions of the spring 13 contract in accordance with the relationship between the spring constant of the spring 13 and the pressing force. The spring 13 may be fixed to at least one of the medium diameter portion 11B and the piston 14.

[0020] FIG. 2 is a schematic diagram showing details of the piston 14 according to the first embodiment. (a) is a side view of the piston 14, (b) is an XX cross-sectional view, and (c) is a YY cross-sectional view. The piston 14 also has a temperature-control flow path 2 through which a temperature-control medium supplied from a temperature regulator flows. The temperature-control flow path 2 is connected to the piston mating pin 11 and the temperature-control flow path 2 machined in the sprue bushing insert 1. The piston 14 is composed of four sections, from the side farthest from the contact surface of the spring 13: a water-stopping section 14A, a tapered section 14B, a cylindrical section 14C, and an inner diameter section 14D. The water-stopping section 14A and the tapered section 14B come into contact with a recess 17 machined in the sprue bushing insert 1 when the piston 14 enters the sprue bushing insert 1 by an operation described below. The cylindrical section 14C has a diameter equivalent to the hole machined in the fixed die 10, and the inner diameter section 14D is machined to come into contact with the outer surface of the cylindrical section of the spring / piston retaining section 12. A positioning lock hole 15, which is a cylindrical or columnar recess, is provided on the outer diameter side of the cylindrical portion 14C. The positioning lock pin 16 is slidable inside a hole formed in the fixed mold 10 perpendicular to the hole that houses the piston 14, and its tip is fitted into the positioning lock hole 15 to fix the piston 14. However, any other structure that can fix the piston 14 may be used.

[0021] Fig. 3 is a flow chart showing an assembly process for the resin molding die according to embodiment 1. Fig. 4 is a schematic cross-sectional view of the temperature adjusting water shut-off mechanism according to embodiment 1 when the piston is retracted. First, holes for inserting the piston fitting pin 11, the spring 13, and the piston 14 are machined in the fixed mold 10 (operation S1).

[0022] The piston fitting pin 11 is inserted into the hole, and the large diameter portion 11A of the piston fitting pin 11 is screwed into the fixed mold 10 with a fixing screw such as a hexagonal bolt to fix them (operation S2).

[0023] Next, the spring 13 and the piston 14 are inserted into the spring / piston holding portion 12 of the piston fitting pin 11 (operation S3).

[0024] As described above, by pressing spring 13 from the piston 14 side, it can be displaced according to the relationship between the spring constant and pressing force of spring 13. This action causes watertight portion 14A located at the tip of piston 14 to be housed closer to the fixed mold 10 than the interface between the fixed mold 10 and sprue bushing insert 1. In this state, positioning lock pin 16 is inserted into positioning lock hole 15 provided in cylindrical portion 14C of piston 14, thereby temporarily fixing the position of piston 14 (operation S4).

[0025] Because the watertight portion 14A of the piston 14 is housed inside the fixed mold 10, the sprue bushing insert 1 can be easily assembled into the fixed mold 10 (operation S5). After the sprue bushing insert 1 is assembled into the fixed mold 10, the positioning lock pin 16 inserted into the positioning lock hole 15 machined in the piston 14 is released (operation S6). This action causes the piston 14 to jump out of the fixed mold 10 toward the sprue bushing insert 1 due to the reaction force of the spring 13.

[0026] At this time, tapered portion 14B machined on piston 14 is positioned along tapered portion 17A machined on the end face of sprue bushing insert 1, so piston 14 can be guided to the desired position. Furthermore, the reaction force of spring 13 presses water stop portion 14A of piston 14 against water stop portion 17B of sprue bushing insert 1, thereby forming a water stop mechanism. At this time, temperature control flow path 2 machined on sprue bushing insert 1 and temperature control flow paths 2 machined on piston 14 and piston mating pin 11 are connected coaxially to form a series of temperature control flow paths 2.

[0027] A temperature control medium supplied from a mold temperature regulator is passed through the temperature control flow path 2, thereby regulating and managing the temperature of the fixed mold 10 and sprue bushing insert 1 and promoting the cooling and solidification of the molten resin flowing into the sprue portion 3. The length of the spring 13 must be such that the reaction force of the spring 13 presses the water stop portion 14A of the piston 14 tightly against the water stop portion 17B of the sprue bushing insert 1, ensuring sufficient water stop performance.

[0028] The length and spring constant of the spring 13 must be determined so that the piston 14 can be pushed toward the spring 13 and housed inside the fixed mold 10. When the piston 14 moves into the sprue bushing insert 1 due to the reaction force of the spring 13, the temperature control medium supplied from the mold temperature controller also flows through the inner diameter portion 14D of the piston 14.

[0029] In the above-described assembly workflow, the positioning lock pin 16 is used to assemble the sprue bushing insert 1 to the fixed die 10 with the piston 14 housed inside the fixed die 10. However, it is also possible to assemble the sprue bushing insert 1 to the fixed die 10 in advance, insert the spring 13 and piston 14 into the spring / piston holding portion 12 of the piston fitting pin 11, and then insert the piston fitting pin 11 into the fixed die 10 and fasten the large diameter portion 11A with a hexagon bolt or the like.

[0030] When the sprue bushing insert 1 is separated from the fixed mold 10 due to periodic maintenance of the resin molding die 100 or the like, the hexagonal bolt or the like fastening the piston fitting pin 11 to the large diameter portion 11A can be loosened, the piston fitting pin 11 can be removed from the fixed mold 10, and then the sprue bushing insert 1 can be removed from the fixed mold 10.

[0031] The inner diameter portion 14D of the piston 14 is fitted so as to come into contact with the spring / piston holding portion 12, but if a gap is formed between the two, there is a risk that the temperature control medium flowing through this path inside the temperature control flow path 2 will leak out of the resin molding die 100. For this reason, it is preferable that the piston 14 be made of an elastic material such as a rubber material, so that no gap is formed between the inner diameter portion 14D of the piston 14 and the spring / piston holding portion 12.

[0032] Meanwhile, to form a water-stopping mechanism, piston 14 is displaced axially of spring / piston holder 12 under the reaction force of spring 13. To ensure smooth displacement in response to the reaction force of spring 13, it is necessary to reduce the sliding resistance between inner diameter 14D of piston 14 and spring / piston holder 12. Therefore, piston 14 is preferably made of silicone rubber or fluororubber, which are rubber materials with excellent sliding properties. These rubber materials have a high heat resistance of 200°C or higher, making them durable even at temperatures of 150°C, which is the temperature-control medium expected when engineering plastics are used for resin molding. When general-purpose plastics are used for resin molding and the temperature-control medium temperature is below 100°C, acrylic rubber or ethylene-propylene-diene rubber may be used with a water-stopping grease applied.

[0033] With the mechanism of the first embodiment described above, the reaction force of the spring 13 presses the water-stopping portion 14A of the piston 14, which is made of a rubber material, firmly against the water-stopping portion of the sprue bushing insert 1, thereby maintaining water-stopping performance for a long period of time. Furthermore, by forming the piston 14 from a rubber material, the piston deforms to conform to the shape of the water-stopping surface, thereby minimizing gaps in the water-stopping portion, improving water-stopping performance, and reducing the risk of gaps in the water-stopping portion due to crevice corrosion, ensuring long-term reliability of water-stopping performance. Furthermore, by operating the positioning lock pin 16 while the piston 14 is housed inside the fixed mold 10, the workability of assembling the sprue bushing insert 1 into the fixed mold 10 is improved.

[0034] Furthermore, when forming a water-stopping mechanism using an O-ring, it is desirable that the direction of compression of the O-ring and the water-stopping surface are parallel. This is because if the two are perpendicular, there is a high risk that the O-ring will be twisted or damaged when the insert with the temperature control piping is assembled into the main mold, resulting in a decrease in sealing performance. This increases the length of the temperature control piping, raising concerns about increased processing costs and reduced cooling efficiency. In contrast, with the water-stopping mechanism of embodiment 1, the position of the piston 14 can be fixed while it is housed inside the fixed mold 10, eliminating any interference when assembling the insert with the temperature control piping into the fixed mold. This has the advantage of increasing design freedom without having to worry about the routing of the temperature control flow path.

[0035] Embodiment 2 5 and 6 are cross-sectional schematic diagrams showing the piston retracting and advancing of the temperature adjusting water shutoff mechanism of the resin molding die according to embodiment 2. Detailed explanations of the same mechanisms as those in embodiment 1 will be omitted.

[0036] In the second embodiment, the shape of piston 24 is improved. That is, while in the first embodiment, inner diameter portion 14D of piston 14 and inner diameter of water stop portion 14A are machined to have the same diameter, inner diameter portion 24D of piston 24 in the second embodiment and inner diameter of water stop portion 24A have different diameters. That is, the inner diameter of opening 24E of water stop portion 24A is smaller than inner diameter portion 24D of piston 24, and an opening is formed with the same diameter as small diameter portion 11C of spring / piston holding portion 12. That is, the tip of water stop portion 24A other than the formed opening is a flat surface portion that protrudes toward the inner diameter side, as shown in FIG. 6.

[0037] That is, when piston 24 is pushed toward spring 13 to compress spring 13, as shown in Figure 5, the flat surface portion formed around opening 24E of watertight portion 24A comes into contact with the tip of spring / piston holding portion 12, preventing piston 24 from being moved back any further. This clearly determines the most retracted position to which piston 24 is pushed in order to compress spring 13. When piston 24 is moved back to the most retracted position, the central axes of positioning lock hole 15 provided in cylindrical portion 24C of piston 24 and positioning lock pin 16 coincide. This mechanism provides a guide for the amount of retraction of piston 24, improving the ease of inserting positioning lock pin 16 into positioning lock hole 15 to fix the position of piston 24. Furthermore, forming a flat surface portion on water-stopping portion 24A increases the radial length of water-stopping portion 24A of piston 24, thereby increasing the contact distance (water-stopping distance) with water-stopping portion 17B. This is expected to improve water-stopping performance.

[0038] Embodiment 3 7 and 8 are cross-sectional schematic diagrams showing the temperature adjusting water shutoff mechanism of the resin molding die according to embodiment 3 when the piston moves backward and forward. Detailed explanations of mechanisms similar to those in embodiment 2 will be omitted.

[0039] In the third embodiment, the shape of the spring / piston retaining portion 32 is improved. In the first and second embodiments, the watertightness at the interface between the inner diameter portions 14D, 24D of the pistons 14, 24 and the spring / piston retaining portion 12 is maintained by the reaction force of the rubber material that constitutes the pistons 14, 24. In contrast, in the third embodiment, an O-ring fitting portion 18 is machined and formed near the tip of the spring / piston retaining portion 32, and an O-ring 19 is fitted inside the O-ring fitting portion 18. The piston 34 is a rigid body made of a metal material or a resin material, and the O-ring 19 is compressed between the inner diameter portion 34D of the piston 34 and the O-ring fitting portion 18.

[0040] This mechanism ensures watertightness at the interface between the inner diameter portion 34D of the piston 34 and the spring / piston retaining portion 32. The reaction force of the spring 13 also improves the sliding properties of the piston 34 when it moves into the interior of the sprue bushing insert 1, improving the positioning and watertightness of the piston 34. Furthermore, in the process of fixing the advanced position of the piston 34 by inserting the positioning lock pin 16 into the positioning lock hole 15 provided in the cylindrical portion 34C of the piston 34, the holding force of the positioning lock pin 16 is improved, which is expected to improve the ease of assembling the sprue bushing insert 1 to the fixed die 10.

[0041] Embodiment 4 9 and 10 are cross-sectional schematic diagrams showing the piston retracting and advancing of the temperature adjusting water shutoff mechanism of the resin molding die according to embodiment 4. Detailed explanations of the same mechanisms as those in embodiment 3 will be omitted.

[0042] In the fourth embodiment, the shape of the piston 44 is improved. In the third embodiment, the piston 34 is made of a rigid metal or resin material to improve the sliding properties, positioning, and watertightness of the piston 34 due to the reaction force of the spring 13. In contrast, in the present embodiment, the tip of the piston 44 is made of an elastic body 20 such as an elastomer. The elastic body 20 can be integrated into the tip of the piston 44 made of a metal or resin material by insert molding or two-color molding. Alternatively, the elastic body 20 made of a rubber material may be integrated by fitting into a concave-convex shape provided on the tip of the piston 44. This mechanism, similar to the third embodiment, improves the sliding properties and positioning of the piston 44 due to the reaction force of the spring 13, while also ensuring watertightness of the tip of the piston 44.

[0043] Although the present disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not exemplified are conceivable within the scope of the technology disclosed in the specification, including, for example, cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with components of another embodiment.

[0044] Various aspects of the present disclosure are summarized below as appendices.

[0045] (Appendix 1) In a resin molding mold having a water-stop mechanism for connecting to a flow path of a temperature control medium formed in another mold, The water-stopping mechanism comprises a piston fitting pin fixed to a hole formed in the mold and having a temperature control piping formed inside it, an elastic member inserted into the piston fitting pin and arranged within the hole, a piston fitted to the piston fitting pin and engaging with the elastic member while being movable in the longitudinal direction of the piston fitting pin, and a fixing member that fixes the piston so that it is stored within the hole against the elastic force of the elastic member, and when connecting to a flow path of the other mold, the piston is advanced into the other mold by releasing the fixing member, and the tip of the piston presses against the periphery of the flow path of the other mold due to the elastic force of the elastic member, thereby stopping water. (Appendix 2) 2. The resin molding die according to claim 1, wherein the piston is made of an elastic material. (Appendix 3) 2. The resin molding die according to claim 1, wherein the tip of the piston is formed of an elastic material, and the rest of the piston is formed of metal or resin. (Appendix 4) The resin molding die according to any one of claims 1 to 3, wherein the fixing member is a convex member that fits into a recess formed in the piston from outside the hole. (Appendix 5) The resin molding mold according to any one of claims 1 to 4, characterized in that the side surface of the piston is tapered so as to be positioned along the inlet of a tapered flow path formed in the end surface of the other mold. (Appendix 6) The resin molding die according to any one of appendixes 1 to 5, wherein a tip of the piston has a planar portion protruding toward an inner diameter side, and when the piston is stored, this planar portion comes into contact with a tip of the temperature control piping formed on the piston fitting pin. (Appendix 7) A resin molding die according to any one of claims 1 to 6, characterized in that a gap for inserting an O-ring is formed around the tip of the piston fitting pin to which the piston is fitted. (Appendix 8) 8. The resin molding die according to any one of claims 1 to 7, wherein the other die is a sprue bush insert. [Explanation of symbols]

[0046] 1: sprue bushing insert, 2: temperature control flow path, 3: sprue portion, 10: fixed type, 11: piston mating pin, 12, 32: spring / piston holding portion, 13: elastic member (spring), 14, 24, 34, 44: piston, 15: positioning lock hole, 16: positioning lock pin, 18: O-ring mating portion, 19: O-ring, 20: elastic body.

Claims

1. In a resin molding mold having a water-stop mechanism for connecting to a flow path of a temperature control medium formed in another mold, The water-stopping mechanism comprises a piston fitting pin fixed to a hole formed in the mold and having a temperature control piping formed inside it, an elastic member inserted into the piston fitting pin and arranged within the hole, a piston fitted to the piston fitting pin and engaging with the elastic member while being movable in the longitudinal direction of the piston fitting pin, and a fixing member that fixes the piston so that it is stored within the hole against the elastic force of the elastic member, and when connecting to a flow path of the other mold, the piston is advanced into the other mold by releasing the fixing member, and the tip of the piston presses against the periphery of the flow path of the other mold due to the elastic force of the elastic member, thereby stopping water.

2. 2. The resin molding die according to claim 1, wherein the piston is made of an elastic material.

3. 2. The resin molding die according to claim 1, wherein the tip of the piston is made of an elastic material, and the rest of the piston is made of metal or resin.

4. 4. The resin molding die according to claim 1, wherein the fixing member is a convex member that is fitted into a recess formed in the piston from outside the hole.

5. 4. A resin molding die according to claim 1, wherein the side surface of the piston is tapered so as to be positioned along an inlet of a tapered flow path formed in an end surface of the other die.

6. 4. A resin molding die according to claim 1, wherein the tip of the piston has a planar portion that protrudes toward the inner diameter side, and when the piston is stored, this planar portion comes into contact with the tip of the temperature control piping formed on the piston fitting pin.

7. 4. The resin molding die according to claim 1, wherein a gap for inserting an O-ring is formed around the tip of the piston fitting pin to which the piston is fitted.

8. 4. The resin molding die according to claim 1, wherein the other die is a sprue bush insert.

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