JP2005119181A - Apparatus for producing annular molding, mold, and injection molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for producing an annular molding which can stably obtain a homogeneous molding faithfully reproducing the design quality of a mold surface and shorten a time necessary for a molding cycle, a mold, and an injection molding method. <P>SOLUTION: A heating medium channel 11 in which a heating medium and a cooling medium for adjusting the temperature of a core piece 2 is formed in the core piece 2. The channel 11 has an annular shape to surround a valve gate 1A and a cavity 1 and is formed to be equally separated from the valve gate 1A and the cavity 1. The gaseous heating medium as a heating medium or the liquid cooling medium is supplied from a heating medium supply apparatus to the channel 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a manufacturing apparatus, a mold and an injection molding method for a hollow annular molded product having a central hole inside.

  Conventionally, an annular cavity formed between a fixed mold plate and a movable mold plate is conventionally known when a precision annular molded product such as a flange, a roller, a gear, and a disk is obtained by injection molding. An injection molding method is known in which resin is supplied through a valve gate of a hot runner (see, for example, Patent Document 1).

  Further, a valve gate mold apparatus in which a first heater is provided on the outer peripheral portion of the hot runner valve main body and a second heater for assisting heating of the tip end portion of the valve main body is provided inside the fixed side mold plate. Is known (see, for example, Patent Document 2). In order to maintain the molten state at the tip of the gate, deterioration may be promoted depending on the resin material in the resin passage of the valve body if the heating is always performed. In order to compensate for the heat radiation effect on the fixed / movable template side at the tip of the valve body, a second heater is provided. However, in the case of a thermoplastic resin, in the case of a thermoplastic resin, the cycle may be extended by taking more than necessary to cool and solidify the inside of the cavity, which is not always a satisfactory method.

  Further, a method for adjusting the temperature of an injection mold that repeats heating and cooling alternately and in a short time using a heat medium is conventionally known. In order to switch between heating and cooling of the mold cavity surface in a short time, for example, an injection mold having a series of flow paths through which a heating medium and a cooling medium flow alternately is known. (For example, refer to Patent Document 3).

There is also known a method for adjusting the temperature of an injection mold using steam as a heating medium and a cooling medium, heating by increasing the vapor pressure in the mold flow path, and cooling by decreasing the vapor pressure ( For example, see Patent Document 4).
Japanese Patent No. 3246434 JP 2003-165141 A JP 2001-18229 A JP 2002-316341 A

  However, in the case of Patent Document 4, the vapor pressure is controlled, the temperature is not actively adjusted, and the temperature adjustment of the gate portion in the hot runner valve gate system is not considered. For this reason, the temperature adjustment resulting from the distance difference between the gate portion and the heat medium flow path is not sufficient, and it may be considered that the uniform control of the resin temperature is insufficient. In addition, if the resin temperature varies partially, it becomes difficult to accurately control the internal pressure of the resin, and in the case of an annular molded product in particular, it is possible to stably obtain a homogeneous molded product that faithfully reproduces the design quality of the mold surface. In some cases, it could cause problems.

  Therefore, the present invention has been made in view of the problems of the prior art described above, and an annular molded product manufacturing apparatus that can stably obtain a homogeneous molded product that faithfully reproduces the design quality of the mold surface, A first object is to provide a mold and an injection molding method. It is a second object of the present invention to provide an apparatus for manufacturing an annular molded product, a mold, and an injection molding method that can shorten the time required for the molding cycle.

  In order to achieve the above object, an apparatus for manufacturing an annular molded product according to the present invention fills a cavity with molten resin from a valve gate of a mold in which a cavity including an annular portion and an annular valve gate communicating with the cavity are formed. In the annular molded product manufacturing apparatus for molding a molded product including an annular portion, a movable pin that opens and closes the valve gate and pressurizes the molten resin in the valve gate and the cavity in a closed state, and in the mold, Heat medium supply means for supplying a heat medium for heating and cooling the molten resin in the valve gate and the cavity to the annular portion of the cavity and the heat medium flow path disposed at a substantially equal distance from the valve gate. It is characterized by.

  The apparatus for manufacturing an annular molded article of the present invention configured as described above supplies a heat medium to the heat medium flow path disposed at a substantially equal distance from the annular portion of the cavity and the valve gate by the heat medium supplying means. As a result, the molten resin in the cavity and the valve gate can be heated uniformly, and solidification of the molten resin in the cavity can be delayed to prevent a decrease in fluidity. The molten resin that has been uniformly heated and whose fluidity has been prevented from being lowered will circulate well into the cavity. Since the molten resin wraps well into the cavity, the pressure applied by the movable pin is uniformly applied to the molten resin, so that the mold surface properties are faithfully transferred. As a result, a homogeneous molded product that faithfully reproduces the design quality of the mold surface can be stably obtained.

  The annular molded article manufacturing apparatus of the present invention is provided such that the movable pin is fitted to the support pin forming the cavity and is slid in the moving direction of the support pin to open and close the valve gate. It may be.

  Further, in the annular molded product manufacturing apparatus of the present invention, the heat medium supply means includes a gas supply means for supplying a gas as a heat medium for heating to the heat medium flow path when the molten resin is filled, and a cooling medium when the molded product is cooled and solidified. It may have a liquid supply means for supplying a liquid as a cooling heat medium to the heat medium flow path. For example, by using steam at 150 to 300 ° C. pressurized to 0.8 to 1.0 MPa during heating, the time required for heating the mold can be shortened compared to using hot water at around 100 ° C. Can do. Furthermore, by using cooling water during cooling, the same medium is used for both heating and cooling, and switching of the heating medium from heating to cooling or from cooling to heating is quick and easy. Thereby, a shaping | molding cycle can be shortened.

  The mold of the present invention is a mold for forming an injection molded product including an annular part by filling a molten resin from the valve gate, in which a cavity including an annular part and an annular valve gate communicating with the cavity are formed. In the mold, a heat medium flow path is formed that is disposed at an approximately equal distance from the annular portion of the cavity and the valve gate, and is supplied with a heat medium for heating and cooling the molten resin in the valve gate and the cavity. It is characterized by.

  Further, in the mold of the present invention, the heat medium flow path may have an annular portion.

  An injection molding method of the present invention is an injection molding method for molding an injection molded product including an annular portion by filling a molten resin, and includes a cavity including an annular portion, an annular valve gate communicating with the cavity, A step of preparing a mold in which a heat medium flow path is formed at a substantially equal distance from the annular portion and the valve gate; a step of supplying a heat medium for heating to the heat medium flow path when filling the molten resin; and a valve There are a step of pressurizing the molten resin in the valve gate and the cavity by the opening / closing means for opening and closing the gate, and a step of supplying a cooling heat medium to the heat medium flow path when the molded product is cooled and solidified.

  In the injection molding method of the present invention as described above, the molten resin in the cavity and the valve gate is uniformly distributed in order to supply the heat medium to the annular portion of the cavity and the heat medium flow path arranged at an approximately equal distance from the valve gate. And the solidification of the molten resin in the cavity can be delayed to prevent a decrease in fluidity. In this way, pressure is applied to the molten resin that has been heated uniformly and suppressed in fluidity, so that the mold surface properties are faithfully transferred. As a result, a homogeneous molded product that faithfully reproduces the design quality of the mold surface can be stably obtained.

  The injection molding method of the present invention may include a step of supplying a gas as a heating heat medium and a step of supplying a liquid as a cooling heat medium. Thereby, since a long time is not required for heating of a metal mold | die, a molding cycle can be shortened.

  According to the present invention, a homogeneous annular molded product that faithfully reproduces the design quality of the mold surface by supplying the heat medium to the heat medium flow path disposed at an approximately equal distance from the annular portion of the cavity and the valve gate. It can be obtained stably. In addition, the time required for the molding cycle can be shortened by supplying a liquid as a cooling heat medium during cooling and solidification.

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

  FIG. 1 shows a cross-sectional view of a mold structure of an example of an injection mold for annular molded products in the present invention. FIG. 2 is a schematic diagram showing the relationship between the heat medium flow path, the valve gate, and the cavity.

  An injection mold for an annular molded product of the present invention is obtained by filling the cavity 1 in the figure with molten resin and then cooling and solidifying to obtain an annular molded product, which is provided on the fixed mold plate side (not shown). It has the core piece 2 and the cavity piece 3 provided in the movable mold plate side not shown. On the core piece 2 side, a valve body 6 in which a heater (not shown) for keeping the internal resin in a molten state is incorporated, and a cylindrical movable body slidably attached to the valve body 6 are provided. A pin 7, a support pin 4 provided on the fixed mold plate side, and a heat insulating ring 9 are provided. Further, on the core piece 2 side, a heat medium flow path 11 that is a flow path through which a heating medium and a cooling medium flow for temperature adjustment is formed. On the other hand, on the cavity piece 3 side, a core pin 5 for forming an inner peripheral surface of the cavity 1 having the shape of an annular molded product is provided.

  The outer peripheral surface of the cavity 1 forming the shape of the annular molded product is formed by attaching the core piece 2 and the cavity piece 3 together. Further, the inner peripheral surface of the cavity 1 is formed by attaching a support pin 4 provided on the fixed mold side and a core pin 5 provided on the movable mold side. The support pin 4 is attached to a valve gate type hot runner body (not shown).

  A molten resin flow path 8 is formed between the movable pin 7 and the valve body 6, and the molten resin is supplied from a molten resin supply source (not shown), passes through the molten resin flow path 8, and further is a valve gate. The cavity 1 is filled through 1A.

  The movable pin 7 has a function of opening and closing the valve gate 1 </ b> A and a function of applying pressure to the molten resin in the cavity 1 by the tip portion thereof. The movable pin 7 is slidably provided with respect to the valve body 6, and a concentric support pin 4 is slidably provided therein. The movable pin 7 descends to close the valve gate 1A, which is a molten resin supply port to the cavity 1, stops supply of the molten resin to the cavity 1, and applies a predetermined pressure to the molten resin in the cavity 1. .

  The heat insulating ring 9 is for preventing the heat of the valve main body 6 from being transmitted to the core piece 2, and when the valve main body 6 is disposed on the core piece 2, the receiving surface is received by the heat insulating ring 9. . This prevents heat from the valve body 6 from being radiated through the core piece 2 connected to the outside of the mold.

  The resin heat insulating portion 10 formed between the valve main body 6 and the core piece 2 at the lower part of the valve main body 6 is a heat insulating region for preventing the heat of the valve main body 6 from being transmitted to the core piece 2. It is a cavity at the start of the first molding, and then it is filled with a solidified resin.

  The heat medium flow path 11 formed in the core piece 2 is a flow path through which a heating medium and a cooling medium flow for adjusting the temperature of the core piece 2. As shown in FIG. 2, the heat medium flow path 11 has an annular shape surrounding the valve gate 1 </ b> A and the cavity 1, and is formed to have a substantially equal distance from the valve gate 1 </ b> A and the cavity 1. . The heat medium flow path 11 is connected to a heat medium supply device (not shown) such as a pump, and a gas heating medium or a liquid cooling medium is supplied as a heat medium from the heat medium supply apparatus. The gaseous heating medium or liquid cooling medium supplied from the heat medium supply device is adjusted to a predetermined temperature by the temperature adjustment device and then supplied to the heat medium flow path 11 by the heat medium supply device. Note that the heat medium supply device and the temperature adjustment device may be configured integrally.

  Note that the same kind of medium is preferably used for both the gaseous heating medium and the liquid cooling medium. This is because the medium can be switched quickly and easily during heating and cooling. For example, when filling the cavity 1 with resin, pressurized water vapor is supplied as a gaseous heating medium into the heat medium flow path 11, and cooling water is supplied as a liquid cooling medium into the heat medium flow path 11 during cooling and solidification. It may be supplied. The heat medium is not limited to water, and other types of heat medium such as oils may be used. The water vapor pressure is preferably in the range of 0.8 to 1.0 MPa, but is not particularly limited thereto. Moreover, although the temperature of water vapor | steam is suitable for the range of 150-300 degreeC, it is not limited to this.

  The core piece 2 provided on the fixed mold plate is provided with a conical convex taper portion 2 </ b> A so as to surround the cavity 1. Further, the cavity piece 3 provided on the movable mold plate is provided with a conical concave taper portion 3A so as to abut on the conical convex taper portion 2A of the core piece 2. The position accuracy of the core piece 2 and the cavity piece 3 is corrected by the convex taper portion 2A and the concave taper portion 3A, and it is possible to always match not only the mechanical accuracy but also the same position. Thereby, the positional accuracy at the time of abutting of the outer peripheral part of the cavity 1 is remarkably improved. Further, it is possible to suppress misalignment between the mold clamping direction (the vertical direction in the drawing) and the vertical plane during molding. Furthermore, by improving the positional accuracy of the core piece 2 and the cavity piece 3, the positional accuracy of the support pin 4 attached to the core piece 2 and the core pin 5 attached to the cavity piece 3 can be greatly improved. . In this embodiment, a convex taper portion 2A is formed on the core piece 2, and a concave taper portion 3A is formed on the cavity piece 3. However, a concave taper portion is formed on the core piece 2, and a convex taper portion is formed on the cavity piece 3. May be.

  Further, the abutment surface of the support pin 4 with respect to the core pin 5 is provided with a substantially conical concave taper portion 4A, and the abutment surface of the core pin 5 with respect to the support pin 4 is provided with a substantially conical convex taper portion 5A. It has been. The positional accuracy of the core pin 5 of the support pin 4 is corrected by abutting the concave taper portion 4A and the convex taper portion 5A, and the respective axial centers can be aligned with the designed center line. The centering accuracy of the circumference is greatly improved. Further, it is possible to suppress misalignment between the mold clamping direction (the vertical direction in the drawing) and the vertical plane during molding. In this embodiment, the support pin 4 has a concave taper portion 4A and the core pin 5 has a convex taper portion 5A, but the core pin 5 may have a concave taper portion and the support pin 4 may have a convex taper portion. good.

  Each shape of the convex taper portion 2A and the concave taper portion 3A, and the concave taper portion 4A and the convex taper portion 5A needs to be designed in consideration for preventing the meshing at the time of matching. That is, if the leveling surface of the step is a right angle or an angle close to this, it is necessary to match the above-mentioned matching part with extremely high accuracy. Further, if the curved surface is not a simple curved surface but a complicated curved surface, the desired positional accuracy and quick positioning can be ensured, but the processing cost increases. In the present embodiment, the convex taper portion 2A and the concave taper portion 3A and the concave taper portion 4A and the convex taper portion 5A are smoothly and accurately abutted by appropriately rounding each apex of each taper portion to a C surface or lightly. It can also be possible.

  Next, the manufacturing process of the annular molded product by the injection mold will be described with reference to FIGS. FIG. 3 shows a state before the molten resin is injected into the cavity 1. FIG. 4 is a view showing a state in which the valve gate 1A is closed after the molten resin is injected into the cavity 1. FIG. 5 is a flowchart for explaining the manufacturing process of the annular molded product of this embodiment. 3 and 4, the same members as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  First, the movable mold plate and the cavity piece 3 attached thereto are moved toward the fixed die plate and the core piece 2 attached thereto (in the vertical direction in FIG. 3), and are abutted with a predetermined pressure (step S1). ). At this time, the core piece 2 and the cavity piece 3 are abutted while being aligned smoothly and accurately by the convex taper part 2A of the core piece 2 and the concave taper part 3A of the cavity piece 3.

  Next, the support pin 4 is slid downward with respect to the movable pin 7 and the core pin 5 is slid upward with respect to the cavity piece 3 so that the support pin 4 and the core pin 5 are abutted ( Step S2). At this time, the positions of the support pin 4 and the core pin are within a predetermined range by the alignment of the core piece 2 and the cavity piece 3 described above. By the concave taper portion 4A of the support pin 4 and the convex taper portion 5A of the core pin 5, the support pin 4 and the core pin 5 are abutted so that the respective axes are aligned smoothly. Therefore, even if the axis is displaced by the clearance between the support pin 4 and the movable pin and the clearance between the core pin 5 and the cavity piece 3, there is no step on the inner peripheral surface of the cavity 1.

  Next, a molten resin is supplied from a resin supply source (not shown) into the molten resin flow path 8, and the molten resin is poured into the cavity 1 along the direction of the arrow in FIG. 2 (step S3). At this time, since the molten resin is continuously heated by the heater built in the valve body 6, a stable molten state can be maintained.

  When the first molding is performed after the mold is closed by the fixed mold plate and the movable mold plate, since the resin heat insulating portion 10 is a cavity, the molten resin is first filled in the resin heat insulating portion 10 and then flows into the cavity 1. Since the resin of the resin heat insulating part 10 is solidified after the first molding, the molten resin flows directly into the cavity 1 without passing through the resin heat insulating part 10.

  When the molten resin passes through the valve gate 1A, the core piece 2 is heated by flowing 150 to 300 ° C. steam pressurized to 0.8 to 1.0 MPa as a heating medium through the heat medium flow path 11 (step) S4). Since the temperature is higher than that of hot water, it is possible to further suppress a decrease in fluidity of the molten resin when the molten resin flows into the cavity 1. Further, since the annular heat medium flow path 11 is formed at an equal distance from the annular valve gate 1A and the cavity 1, not only the cavity 1 but also the molten resin in the valve gate 1A is heated uniformly. . In this way, the molten resin that has been heated uniformly and suppressed in fluidity can improve the filling balance, so that the molten resin can be smoothly wrapped in the cavity 1.

  Next, after the cavity 1 is filled with resin, the movable pin 7 is moved in the direction of the cavity 1 while sliding with respect to the core piece 2 and the support pin 4 (step S5). By the downward movement of the movable pin 7, the resin material in the cavity 1 is compressed (holding pressure) smoothly and uniformly directly on the end face of the annular molded product from the resin filling direction. At the same time, the valve gate 1A is closed, and the flow into the resin cavity 1 of the molten resin flow path 8 stops. At this time, force is applied to the support pin 4 and the core pin 5 in the direction perpendicular to the mold clamping direction, but the support pin 4 and the core pin 5 are displaced from each other because they are positioned with respect to each other by the concave taper portion 4A and the convex taper portion 5A. There is nothing. Similarly, the convex taper portion 2A provided on the core piece 2 and the concave taper portion 3A provided on the cavity piece 3 do not shift the positions of the core piece 2 and the cavity piece 3.

  As described above, since the molten resin has satisfactorily entered the cavity 1 by heating evenly, the pressure by the movable pin 7 is uniformly applied. Then, the uniformity of the internal pressure distribution is achieved, whereby the mold surface properties are faithfully transferred.

  Next, in order to cool the resin filled in the cavity 1, after the valve gate 1A is closed, cooling water is poured into the heat medium passage 11 as a cooling medium (step S6). Thus, the heated mold, that is, the core piece 2 and the cavity piece 3 are rapidly cooled to solidify the molten resin in the cavity 1. Further, since the annular heat medium flow path 11 is formed at an equal distance from the annular portion of the cavity 1, the molten resin in the annular portion of the cavity 1 can be cooled uniformly.

  In the case of the present embodiment, as the heat medium flowing through the heat medium flow path 11, steam is used for heating and cooling water is used for cooling. That is, since both are water, switching of the heat medium by the heat medium supply device can be performed quickly and easily. Thereby, a shaping | molding cycle can be shortened.

  During cooling, a temperature distribution often occurs in the cavity 1, so that force is applied to the support pin 4 and the core pin 5 in a direction perpendicular to the mold clamping direction. In the present embodiment, however, the support pin 4 and the core pin 5 are for the reasons described above. The position of will not shift.

  When the cooling and solidification of the molten resin is completed, the movable mold plate is moved to open the mold (step S7). Thereby, the butting between the cavity piece 3 and the core piece 2 and between the support pin 4 and the core pin 5 is released. Further, the molded product is ejected from the cavity 1 by an unillustrated ejector pin (step S8).

  As described above, through the respective steps according to the manufacturing method of the present embodiment, it is possible to obtain a molded product in which a desired design quality is ensured in which the mold surface properties are faithfully transferred.

  Thereafter, it is determined whether or not to repeat the above process (step S9), and if it is repeated, the process returns to step S1, the mold is closed again, and the above process is repeated.

  In addition, according to the present embodiment, the position accuracy when the support pin 4 and the core pin 5 are abutted by the abutment of the concave taper part 4A provided on the support pin 4 and the convex taper part 5A provided on the core pin 5 is achieved. Can be increased. In addition, it is possible to suppress a shift in the direction perpendicular to the clamping direction with respect to an external force generated due to holding pressure or cooling during molding.

  In addition, the clamping accuracy of the core piece 2 and the cavity piece 3 can be increased by clamping the convex taper part 2A provided on the core piece 2 and the concave taper part 3A provided on the cavity piece 3. In addition, it is possible to suppress a shift in the direction perpendicular to the mold clamping direction with respect to an external force generated due to supplementary pressure or cooling during molding. Further, the positional accuracy of the core piece 2 and the cavity piece 3 is improved, so that the positional accuracy of the support pin 4 attached to the core piece 2 and the core pin 5 attached to the cavity piece 3 falls within a predetermined range. Can do.

  In the present embodiment, since the receiving surface when the valve body 6 is disposed on the core piece 2 is received by the heat insulating ring 9, the heat of the heater embedded in the valve body 6 is applied to the core piece 2. It is difficult to communicate. Since the heated valve body 6 is a metal body, if it is in direct contact with the core piece 2, the heat of the valve body 6 is dissipated through the core piece 2 connected to the outside of the mold, and the temperature control of the molten resin is sufficient. It becomes impossible to. The heat insulating ring 9 also serves to prevent excess resin from flowing out from the resin heat insulating portion 10 filled with resin at the initial stage of injection molding via the clearance 7A. The material of the heat insulating ring 9 may be organic or inorganic, but a material having heat resistance and low thermal conductivity is preferable.

  Further, as described above, the support pin 4 and the core pin 5 are in contact with the concave taper portion 4A and the convex taper portion 5A of the core pin 5, but since the support pin 4 is close to the heated molten resin, it is made of a metal body. Heat escapes via a certain core pin 5. Therefore, heat dissipation is prevented by providing a heat insulating material layer on the surface where both are in contact. Said heat insulation layer may be provided in both the support pin 4 and the core pin 5, and may be provided only in one side. Further, it is a heat insulating material, and any organic or inorganic material may be used as long as appropriate durability can be obtained. Examples of the heat insulating material include those containing an air layer, for example, powder, fibrous body, porous body, layered body, honeycomb structure, etc., and the material is ceramics or high melting point resin, for example, , Silicone and engineering plastics. Moreover, the material and structure may be appropriately combined. Examples of means for installing the heat insulating layer include coating and adhesion.

  Further, the timing of flowing the heating medium through the heat medium flow path 11 is, for example, from after the molded product is taken out during the molding cycle until the gate is closed, thereby suppressing a decrease in fluidity of the molten resin and improving transferability to the mold. Let In addition, the mold temperature is rapidly cooled by flowing a cooling medium in order to cool and solidify the molten resin in the cavity after the gate is closed until the molded product is taken out. By performing rapid heating and cooling of the mold temperature and adjusting the mold temperature to an optimum mold temperature, it is possible to optimize the accuracy of the molded product and the molding cycle.

It is typical sectional drawing of the metal mold | die in one Embodiment of the manufacturing apparatus of the cyclic molded product of this invention. It is a schematic diagram which shows the relationship between a heat medium flow path, a valve gate, and a cavity. It is sectional drawing of the metal mold | die shown in FIG. 1, and shows the time of valve gate opening. It is sectional drawing of the metal mold | die shown in FIG. 1, and shows the time of valve gate closing. It is a flowchart of the manufacturing process in one Embodiment of the injection molding method of the annular molded product of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cavity 1A Valve gate 2 Core piece 2A Convex taper part 3 Cavity piece 3A Concave taper part 4 Support pin 4A Concave taper part 5 Core pin 5A Convex taper part 6 Valve body 7 Movable pin 7A Clearance 8 Molten resin flow path 9 Heat insulation ring 10 Resin Heat insulation part 11 Heat medium flow path

Claims (7)

An annular molding for forming a molded article including an annular portion by filling the cavity with molten resin from the valve gate of a mold in which a cavity including an annular portion and an annular valve gate communicating with the cavity are formed. Product manufacturing equipment,
A movable pin that opens and closes the valve gate and pressurizes the molten resin in the valve gate and the cavity in a closed state;
A heat medium for heating and cooling the molten resin in the valve gate and in the cavity is disposed in the mold in the annular portion of the cavity and the heat medium flow path disposed at an approximately equal distance from the valve gate. An apparatus for manufacturing an annular molded product, comprising: a heat medium supply means for supplying. 2. The annular shape according to claim 1, wherein the movable pin is provided so as to be fitted to a support pin forming the cavity and to open and close the valve gate by sliding in a moving direction of the support pin. Molded product manufacturing equipment. The heat medium supply means supplies gas as a heat medium for heating to the heat medium flow path when the molten resin is filled, and heat for cooling to the heat medium flow path when the molded product is cooled and solidified. The apparatus for producing an annular molded product according to claim 1, further comprising a liquid supply unit that supplies a liquid as a medium. In a mold for forming an injection molded product including an annular portion by filling a molten resin from the valve gate, in which a cavity including an annular portion and an annular valve gate communicating with the cavity are formed,
A heat medium flow path is formed that is disposed at a substantially equal distance from the annular portion of the cavity and the valve gate, and is supplied with a heat medium for heating and cooling the molten resin in the valve gate and the cavity. A mold characterized by that. The mold according to claim 4, wherein the heat medium flow path has an annular portion. An injection molding method for molding an injection molded product including an annular portion by filling a molten resin,
Providing a cavity including an annular portion, an annular valve gate communicating with the cavity, and a mold in which a heat medium flow path is formed at an approximately equal distance from the annular portion of the cavity and the valve gate;
Supplying a heat medium for heating to the heat medium flow path when filling the molten resin;
Pressurizing the molten resin in the valve gate and in the cavity by an opening / closing means for opening and closing the valve gate;
An injection molding method including a step of supplying a cooling heat medium to the heat medium flow path when the molded article is cooled and solidified. The injection molding method according to claim 6, comprising a step of supplying a gas as the heat medium for heating and a step of supplying a liquid as the heat medium for cooling.

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