JP4193175B2 - Foam mold and foam molding apparatus - Google Patents

Description

  The present invention provides a foam molding die in which a cavity is formed by two molds, and does not require a raw material injection head to be individually fixed, and a raw material is easily injected into a cavity formed by the foam molding die. The present invention relates to a foam molding apparatus that can be molded efficiently.

  Synthetic resin foam moldings such as polyurethane foam are used as various parts for automobiles and the like. In the case of molding such a synthetic resin foam molded article, for example, the core material is set after the skin is brought into close contact with the mold, and then the raw material is injected and then foamed. There are two types of molding methods: an open injection molding method and a closed injection molding method. Various molding apparatuses such as an apparatus to which the former open injection molding method is applied (for example, Patent Document 1) and an apparatus to which the latter closed injection molding method is applied (for example, Patent Document 2) are considered. In addition, a valve gate device (for example, Patent Documents 3 to 5) having a movable pin for opening and closing the gate in an injection mold for supplying resin into the cavity via the gate is also considered as a related device.

4A is a cross-sectional view for explaining the open injection molding method, and FIG. 4B is a cross-sectional view for explaining the close injection molding method.
The open injection molding method is a method of closing a foam molding die after injecting a foam molding raw material. For example, as shown in FIG. 4 (a), first, the skin 20 is set on the lower mold 21 as one mold, the core material 23 is set on the upper mold 22 as the other mold, and then the foam mold The material is injected by the injection head 24 in a state in which is opened, and then the upper die 22 is closed to perform molding.
The closed injection molding method is a method of injecting a foam molding raw material by closing a lid of a foam molding die. For example, as shown in FIG. 4B, first, the skin 20 is set on the lower mold 21 as one mold, the core material 23 is set on the upper mold 25 as the other mold, and then the upper mold 25 is set. Is closed, and then the raw material is injected from the injection head 26 in the upper mold 25 to perform molding.
The upper mold 25 used in the so-called closed injection molding method is manufactured by incorporating an injection head 26 for injecting a raw material as shown in FIG.

Next, an upper mold 25 used for the closed injection molding method, which is different from FIG. 4B, will be described. FIG. 5 is a partial cross-sectional view in the vicinity of the foaming mold and the injection head used in the closed injection molding method, and FIG. 6 is a cross-sectional view taken along the line AA in FIG. In addition, the same code | symbol is attached | subjected to the same member or a substantially the same quality member.
The upper mold 25 shown in FIGS. 5 and 6 has a cylindrical wall 25 b formed on a predetermined surface 25 a of the upper mold 25. The nozzle 26a of the injection head 26 is inserted along the cylindrical wall 25b, and the flange 26b of the injection head is fixed to the predetermined surface 25a with a bolt 27. With this configuration, urethane as a raw material is injected between the core material 23 and the skin 20 from the nozzle 26a of the injection head 26, and a foamed molded body 28 made of urethane is formed.

As described above, the upper mold used in the closed injection molding method is manufactured by incorporating an injection head, or is manufactured so that the injection head can be fixed with a bolt or the like from vertically above the back surface of the upper mold.
Japanese Patent Laid-Open No. 07-112445 Japanese Patent Laid-Open No. 2003-039447 JP-A-11-227005 JP 2003-011176 A JP 2003-245952 A

  However, when performing the so-called closed injection molding method, there is a problem that it is necessary to provide an injection head for each upper mold. As a result, when a mold is newly produced, an injection head must be provided one by one, which requires labor and costs such as equipment costs and labor costs.

  Therefore, it is conceivable to make the injection head versatile in a form-independent manner and insert it from the back side of the upper mold so that the general-purpose injection head can be reused. However, as explained below, the yield of molded products is reduced. There is a problem that it is not suitable for mass production.

FIG. 7 is a schematic partial cross-sectional view of each molding process when the injection head is generalized and the injection head is inserted from the back side of the mold. (A) is when the head is inserted, (b) is when the raw material is injected, ) Is a cross-sectional view of each process when the raw material is foamed immediately after the injection head is removed after completion of the injection.
In the step of inserting the injection head into the mold, as shown in FIG. 7A, a robot (not shown) that supports the injection head 29 and controls the position of the injection head 29 is operated to move the arrow B in the figure. As shown in FIG. 2, the nozzle 29a of the injection head 29 is aligned with the center of the insertion port 30a of the predetermined surface 25a of the upper mold. The insertion port 30a is formed by a cylinder 30 fitted to a predetermined surface 25a. The inner peripheral surface of the cylinder 30 is perpendicular to the predetermined surface 25a, and is fixed to the predetermined surface 25a by the flange 30b of the cylinder 30. When the injection head 29 is aligned with the center of the insertion port 30a, the nozzle 29a of the injection head 29 is inserted into the insertion port 30a as shown by the arrow C in the figure.
Then, as shown in FIG. 7B, the raw material 31 is injected from the raw material tank (not shown) through the injection head 29, and the injection head 29 is moved in the direction of the arrow D as shown in FIG. And is extracted from the insertion port 30a. Thereafter, when the raw material is foamed, as shown in FIG. 7 (d), the foamed part 31a leaks from the insertion port 30a and cannot be formed into a desired shape.

  As described above, first, it is necessary to align the injection head 29 with the center of the insertion port 30a, resulting in variations in position adjustment. Secondly, when the injection head 29 is inserted into the insertion port 30a, if the position adjustment is not within a predetermined range, the nozzle 29a of the injection head 29 is pressed against the cylinder 30 and an impact is given to the mold. become. Third, since the foaming is performed after the injection head 29 is removed, a part of the foam leaks from the insertion port 30a. These are the main factors, and the yield of foam molded products is poor, making mass production of foam molded products difficult.

  By the way, in order to improve working efficiency, a foam molding apparatus including a plurality of foam molding dies can be considered. FIG. 8 is a schematic view schematically showing the foam molding apparatus. In the foam molding apparatus 40, each foam mold is placed on the turntable 42 in a concentric manner. In the figure, every other open injection mold 41a and close injection mold 41b are arranged. A robot 43 for adjusting the position of the injection head 46 is provided beside the turntable 42. A raw material supply pipe 45 is connected between the robot 43 and the raw material tank 44 so that the raw material can be delivered to the injection head 46 attached to the tip of the arm of the robot 43. On the other hand, each of the closed injection molding type molds 41b incorporates an injection head 41c connected to the raw material tank 44 by a raw material supply pipe 47.

  With this configuration, by rotating the turntable 42 in the direction of arrow D, the open injection mold 41a can be positioned in the vicinity of the injection head 46 attached to the tip of the arm of the robot 43. The raw material can be injected into the mold 41a placed on the top. Similarly, the raw material can be injected into the mold 41b placed on the turntable 42 by each injection head 41c.

  However, since the turntable 42 rotates 360 degrees in the piping system connected between the injection head 41 c of the closed injection type mold 41 b and the raw material tank 44, the piping 47 does not intersect with the rotation of the turntable 42. Thus, there is a problem that piping equipment such as a special joint is required. Moreover, it is necessary to fix the closed injection type mold 41b and the injection head 41c with screws or the like, and there is a problem that it is complicated.

  Therefore, in view of the above problems, the present invention provides a foam molding die that does not require individual fixing of the raw material injection head in a foam molding die that forms a cavity with two molds, and a cavity formed by this foam molding die. An object of the present invention is to provide a foam molding apparatus capable of easily injecting raw materials and efficiently molding with a high yield.

In order to achieve the above object, the foam mold according to the present invention is a foam mold in which a cavity is formed by two molds, and a pair of nozzles of a raw material injection head is formed in one of the molds. A slide member, each elastic body for biasing the pair of slide members so as to close the insertion port, and each housing the slide member partially from both sides of the pair of slide members via each elastic body A pair of slide members, the nozzles of the raw material injection head abut against the pair of slide members and press to form the insertion port, and the insertion port includes A nozzle is inserted .
Here, it is preferable that each box has a U-shaped cross section, and a ridge is attached to the opposing surface of each box on the cavity side. Further, the basket is preferably made of a synthetic resin having ethylene tetrafluoride as a monomer. The surface of the slide member on the side where the nozzle is inserted is preferably tapered so that the interval is narrower in the nozzle insertion direction. The elastic body is preferably a coil spring.

Since the foam molding die of the present invention has the above-described configuration, when the raw material injection head is fitted to the foam molding die, a pair of normally closed ones is inserted along with the insertion of the raw material injection head. The slide member opens to form an insertion port. After injection, the pair of slide members slide and close by the elastic body just by detaching the raw material injection head, so that the raw material injected into the cavity is foamed. The backflow at the time can be prevented. Therefore, it is not necessary to fix a raw material injection head for each foaming mold.
In addition, if a ridge is provided on the opposing surface of each box on the cavity side, the sliding member is pressed with foaming pressure when foaming, so it serves to seal the gap between the pair of sliding members and enters the gap. Absent. In particular, when it is made of a synthetic resin having tetrafluoroethylene as a monomer, its role becomes remarkable.
In addition, since the surface of the slide member on the side of the raw material injection head is tapered, the allowable range of positioning of the raw material injection head performed during the molding is widened, and not only the working efficiency is increased, but also the raw material injection head is inserted. At this time, the impact given to the foaming mold can be eliminated as much as possible due to the position adjustment of the raw material injection head.

  In order to solve the above problems, the foam molding apparatus of the present invention includes a foam molding die of the present invention, a rotary table on which a plurality of foam molding dies are mounted, and an injection robot equipped with the raw material injection head. And a raw material tank for storing raw materials to be sent to the raw material injection head, and a pipe connection is provided between the raw material injection head and the raw material tank.

  Since the foam molding apparatus of the present invention has the above-described configuration, mass production of the foam molded body can be realized using the close injection molding method. Moreover, a foaming molding can be obtained stably, without using a special joint for piping which sends out a raw material.

  The foam molding die of the present invention has a pair of slide members that are normally closed as the raw material injection head is inserted, and after the injection, the pair of slide members is formed by an elastic body simply by removing the raw material injection head. Since the slide slides and closes, backflow when the raw material injected into the cavity is foamed can be prevented. Therefore, the foam molded body can be molded with a high yield, and there is no need to fix a raw material injection head for each foam molding die. Further, by providing a ridge on the opposing surface of each box on the cavity side, the gap between the pair of slide members can be sealed by being pressed against the slide member by foaming pressure during foaming. In addition, the surface of the slide member on the side of the raw material injection head is tapered, so that the allowable range of positioning of the raw material injection head performed during molding is widened, the work efficiency is increased, and the raw material injection head is inserted. In doing so, the impact on the foaming mold can be reduced as much as possible due to the positional adjustment of the raw material injection head. As described above, the foaming mold of the present invention enables generalization of the raw material injection head.

  Further, the foam molding apparatus of the present invention can realize mass production of a foam molded body using a closed injection molding method. Molding can be performed stably without using a special joint for piping for feeding the raw material. Further, the turntable of the foam molding apparatus of the present invention can be used in various ways by placing not only the foam mold of the present invention but also one or more ordinary open injection molds in combination with the foam mold of the present invention. It is also possible to form a foamed molded article by a simple molding process.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a partial cross-sectional view of a foam mold that is the best mode for carrying out the invention. UP in the figure means vertically upward. The foam mold 1 is a closed injection mold, and a predetermined cavity is formed by combining two molds. In the following description, one of the two molds will be described as a lower mold 2 and the other mold as an upper mold 3.
The lower mold 2 which is one of the molds is formed corresponding to one surface of the molded product, and for example, the skin 4 is set. The upper mold 3 which is the other mold is formed corresponding to the other surface of the molded product, and for example, the core material 5 is set therein. The predetermined surface 3a and the core material 5 of the upper mold 3 are provided with holes having a predetermined shape so that the raw material can be injected by the raw material injection head 6. Here, the skin 4 is a member that becomes a relatively clogged layer on the surface of the foam molded body. The core material 5 is, for example, inserted into the cavity to become a part of the foam-molded body in order to prevent a defective portion having a large thickness and slow cooling.
On the predetermined surface 3a of the upper mold 3, a pair of U-shaped boxes 7a are fixedly provided with a predetermined interval. Each box 7a partially accommodates the slide member 7c with various springs such as coil springs and other elastic bodies 7b interposed therebetween. The pair of slide members 7 c slide to form the insertion port 7 of the raw material injection head 6. The surface opposite to the lower mold 2 of the pair of slide members 7c, that is, the surface 7d on the insertion / removal side of the raw material injection head 6 is tapered. This taper surface has a shape in which the interval is narrower with respect to the insertion direction of the nozzle 6 a of the raw material injection head 6. As a result, the surface 7d slides with the slide member 7c moving in the direction of arrow F by the nozzle 6a of the raw material injection head 6 as the raw material injection head 6 moves in the direction of arrow E in the figure. The member 7c can be easily opened. Similarly, as shown in FIG. 1, it is preferable that a tapered surface is formed on the outer periphery of the nozzle 6a of the raw material injection head 6 so as to correspond to the taper of the slide member 7c.
A collar 8 is attached to the opposing surface 7e at the lower end of each box 7a. The rod 8 is preferably heat resistant such as a synthetic resin having tetrafluoroethylene as a monomer.
The foam mold 1 shown in FIG. 1 is a mold used when performing close injection molding, as will be described later.

FIG. 2 is a schematic view of a foam molding apparatus which is the best mode for carrying out the invention. The foam molding apparatus 10 in FIG. 1 is an apparatus in which one or more foam molding dies 1 in FIG.
The foam molding apparatus 10 has a predetermined type and number of molds mounted on a turntable 11. In the figure, the turntable 11 alternately mounts the closed injection molding type foam molding die 1 and the open injection molding type die 12 of FIG. For example, an articulated robot 13 is disposed beside the turntable 11. The raw material injection head 6 is attached to the arm 13 a of the robot 13. A raw material supply pipe 15 from the raw material tank 14 is connected only to the raw material injection head 6. Here, the robot 13 may arrange a plurality of robots 13 in consideration of the size of the mold such as the foaming mold 1 on which the turntable 11 is placed and work efficiency.
The mode of mounting on the turntable 11 is not limited to that shown in FIG. 2, but may be the closed injection molding type foam molding die 1 of FIG. 1 or the closed injection molding type foam molding. Different numbers of the mold 1 and the open injection molding type mold 12 may be mounted. Further, in FIG. 2, the closed injection molding type foam molding die 1 and the open injection molding type die 12 of FIG. 1 are mounted on the same circumference, but on concentric separate circumferences. It may be placed.

The foam molding process by the foam molding apparatus 10 equipped with the foam molding die 1 having the above configuration will be described.
FIG. 3 is a schematic partial cross-sectional view of each step of foam molding in the foam molding die 1. In the foam molding apparatus 10 of FIG. 2, the turntable 11 is rotated so that the foam molding die 1 to be the next target for injecting the raw material is disposed at a predetermined position such as near the tip of the arm 13 a of the robot 13. To. The positioning at this time, for example, can increase the allowable range of about ± 1.0 mm from the prior art to ± 5.0 mm, which is five times as much, so that the work efficiency is improved.
In this state, as shown in FIG. 3A, the raw material injection head 6 is disposed above the pair of slide members 7c. This is performed by operating the robot 13.
Next, as shown in FIG. 3B, the robot 13 is operated to press the nozzle 6a of the raw material injection head 6 in contact with the pair of slide members 7c, and then as indicated by an arrow E in the figure. And move to the foaming mold 1 side by a predetermined distance. Then, the pair of slide members 7c has a tapered surface on the raw material injection head side, and the outer periphery of the nozzle 6a is also tapered, so that the movement of the nozzle 6a of the raw material injection head 6 moves. Accordingly, the pair of slide members 7 c are opened by sliding in the direction indicated by the arrow F, and the insertion port 7 is configured.
Then, the necessary raw material is sent from the raw material tank 14 to the raw material injection head 6 via the pipe 15. At this time, when there are a plurality of raw materials, for example, when there are two types of polyol component and isocyanate component, they are sent to the raw material injection head 6 via the respective pipes, Mixing is performed using a mixer or a mixer attached to the raw material injection head 6, and the stock solution 16 is injected into the cavity from the nozzle 6a. This state is shown in FIG.
Thereafter, as shown in FIG. 3 (d), the nozzle 6a of the raw material injection head 6 fitted in the insertion port 7 of the pair of slide members 7c is moved in the direction of arrow H to be detached. Then, the pair of slide members 7c slides toward the symmetry plane indicated by the arrow I by the coil spring as the elastic body 7b and comes into contact with each other. That is, it is in a state before the nozzle 6a of the raw material injection head 6 is inserted with a gap between the pair of slide members 7c.
Thereafter, the stock solution 16 is foamed. FIG. 3E shows this state. Since the pair of slide members 7c are in contact with each other during foaming, the pair of slide members 7c serve as a kind of lid. That is, the back flow of the foam is prevented. Further, the gap between the flange 8 and each slide member 7c is sealed as much as possible by the pressure in the direction of arrow J during foaming. Thereby, a part of foaming molding 17 is prevented from entering this gap.
Thereafter, as shown in FIG. 3 (f), the foam is removed from the upper mold and the lower mold.
After obtaining one foam molded body 17 with the foam molding die 1 by the above-described series of steps, the turntable 11 is rotated to move the open injection molding type mold 12 to a predetermined position. Through the process of obtaining one foamed molded article with the mold 12. Hereinafter, these steps are repeated.
In the case of the open injection mold 12, the raw material is injected into a predetermined space of the lower mold, the lid is then closed with the upper mold that becomes the lid of the mold 12, and then foamed.

  The best mode for carrying out the invention described above is merely an example of the present invention, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

It is a fragmentary sectional view of the foaming mold which is the best form for implementing invention. It is the schematic of the foam molding apparatus which is the best form for inventing. FIG. 2 is a schematic partial cross-sectional view of each step of foam molding in the foam mold of FIG. 1. (A) is schematic sectional drawing for demonstrating open injection molding, (b) is sectional drawing for demonstrating closed injection molding. It is a fragmentary sectional view showing the conventional foaming mold used for the closed injection molding method and the vicinity of the injection head. It is sectional drawing which follows the AA line of FIG. It is a general | schematic fragmentary sectional view of each process of shaping | molding at the time of trying to insert an injection | pouring head from the back surface of a type | mold by generalizing an injection | pouring head. It is the schematic of the foam molding apparatus provided with two or more foaming molds considered in order to improve work efficiency.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Foaming mold 2 Lower mold 3 Upper mold 4 Skin 5 Core material 6 Raw material injection head 6a Nozzle 7 Insertion port 7a Box 7b Elastic body 7c Slide member 7e Opposing surface 8 １０ 10 Foam molding apparatus 11 Turntable 12 Type 13 Robot 13a Arm 14 Raw material tank 15 Piping

Claims (6)

In a foam mold that forms a cavity with two molds,
Either one of the molds includes a pair of slide members that constitute an insertion port of the nozzle of the raw material injection head, each elastic body that biases the pair of slide members so as to close the insertion port, and each elasticity Each box that accommodates the slide member partially from both sides of the pair of slide members through the body ,
The pair of slide members are configured to slide to form the insertion port by inserting the nozzle of the raw material injection head into contact with and press against the pair of slide members, and the nozzle is inserted into the insertion port. A foaming mold characterized by. Each box has a U-shaped cross section,
The foaming mold according to claim 1, wherein a ridge is attached to an opposing surface of each box on the cavity side.   The foam mold according to claim 2, wherein the ridge is made of a synthetic resin having tetrafluoroethylene as a monomer.   The foam molding according to any one of claims 1 to 3, wherein a surface of the slide member on a side where the nozzle is inserted is tapered so that a gap is narrowed in a nozzle insertion direction. Type.   The foaming mold according to claim 1, wherein the elastic body is a coil spring.   The foam molding die according to any one of claims 1 to 5, a rotary table on which a plurality of foam molding dies are placed, an injection robot equipped with the raw material injection head, and the raw material injection head. A foam molding apparatus, comprising: a raw material tank that stores raw materials; and a pipe connection between the raw material injection head and the raw material tank.

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