JP3087607B2 - Foam mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foaming mold for molding a foamed resin molded product.

[0002]

2. Description of the Related Art For example, a cushion body of an automobile seat is
It is formed of a foamed resin molded product having a folded undercut portion. As a conventional molding die for producing a foamed resin molded product having this undercut portion, for example, as shown in FIG. 6, there is an airbag type foaming molding die 90. As shown in FIG. 6, the foaming mold 90 includes a lower mold 3, an upper mold 4 and a middle mold 5 which form a cavity 2 having the same shape as the foamed resin molded product to be obtained.
Then, as shown in FIG. 6, the cavity 2 has an undercut 25 that is folded inward.

As shown in FIG. 6, the lower die 3 is disposed on a lower die receiving base 73, and the lower die receiving base 73 is further disposed on an airbag 75. The lower mold 3 can be moved up and down by about 20 to 50 mm by expansion and contraction of the airbag 75. The lower mold 3, the lower mold receiving stand 73, and the airbag 75 are housed in the fixed frame 71.

[0006] As shown in FIGS. 6 and 7, the upper die 4 is fixedly provided on an opening / closing frame 72 connected to a fixed frame 71 via a hinge 79. As shown in FIGS. 6 and 7, the middle mold 5 is provided with the hinge 79.
The arm 959 is rotatably fixed to the distal end of the arm 959. And, as shown in FIGS. 6 and 7, the medium size 5
It has a suspension plate 958, and is configured to engage with the contact portion 949 of the upper die 4 by opening the opening / closing frame 72, and to open and close in conjunction with this.

Further, as shown in FIG. 6, the lower mold 3, the upper mold 4 and the middle mold 5 form one cavity 2 by bringing their sealing surfaces into contact with each other. That is, the sealing surface 3 of the lower mold 3
4 and the sealing surface 43 of the upper die 4 and the sealing surface 45 of the upper die 4
The sealing surface 54 of the middle mold 5 is configured to contact each other.

[0006] Next, when manufacturing a foamed resin molded product,
The raw material is injected into the cavity 2 and foamed and expanded.
As a result, as shown in FIG. 8, the expanding raw material fills the cavity 2 while degassing the gas in the cavity 2 through the clearances of the sealing surfaces 34, 43 and the sealing surfaces 45, 54. And cavity 2
The desired foamed resin molded article can be obtained by filling the raw material by foaming and expanding to every corner.

[0007]

However, the conventional foaming mold 90 has the following problems. That is, if the flow of the raw material in the vicinity of the sealing surfaces 34, 43 and the sealing surfaces 45, 54 is not well-balanced, underfilling or burrs may occur. In particular, as shown in FIGS. 9 and 10, near the sealing surfaces 45 and 54 between the upper die 4 and the middle die 5 located at the undercut 25, if the liquid flow rate of the raw material is too low, the material enters the cavity 2. The raw material solidifies while the gas remains.

[0008] Therefore, the obtained foamed resin molded article 980
The undercut portion 985 has a cutout 990 at the tip.
Will occur. On the other hand, if the liquid flow of the raw material is too fast, the raw material is blown out together with the gas and solidified, thereby generating burrs.

In order to prevent such a problem, it is necessary to adjust the clearance between the sealing surfaces 45 and 54 in order to optimize the balance between the liquid flow speeds of the raw materials before starting mass production. The clearance between the sealing surfaces 45 and 54 of the upper mold 4 and the middle mold 5 in the conventional foaming mold 90 is adjusted by adjusting the height of the receiving portion 47 provided on the lower mold 3 as shown in FIG.

In other words, the clearance between the sealing surfaces 45 and 54 is increased by increasing the height of the receiving portion 47 of the lower die 3 and is reduced by lowering the height of the receiving portion 47 of the lower die 3. . However, the receiving portion 47
When the height of the receiving portion 47 is lowered, it is only necessary to cut it off, but it is very difficult to increase the height of the receiving portion 47 once lowered.

Further, even if the adjustment is once performed optimally, the receiving portion 47
The clearance may change due to wear of the tire. Therefore, adjustment of the clearance between the sealing surfaces 45 and 54
It is difficult to fine-tune and very careful. Therefore, it is also difficult to prevent the occurrence of underfill and burrs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it is possible to easily adjust the clearance between an upper mold and a middle mold. It is an object of the present invention to provide a foaming mold capable of preventing the occurrence of foaming.

[0013]

The present invention comprises a lower mold and an upper mold, and the upper mold is provided with the middle mold so as to be openable and closable, and has an undercut between the upper mold and the middle mold. Then, a foamed resin molded article having an undercut portion is formed in a cavity surrounded by the lower mold, the upper mold, and the middle mold, and the liquid flow of the raw material is adjusted at the sealing surface between the upper mold and the middle mold. A foaming mold, wherein the middle mold is provided with a retractable actuator for adjusting the clearance of the sealing surface.

The most remarkable point in the present invention is that the middle die is provided with an actuator which can move forward and backward for adjusting the clearance of the seal surface.
The actuator is provided so that the middle mold can be relatively moved with respect to the upper mold, and is configured so that the clearance between the sealing surfaces of the two can be increased or decreased.

Further, the actuator can be constituted by, for example, any one of a pneumatic type, a hydraulic type and an electromagnetic type. Thus, the relative movement of the middle die to the upper die can be easily performed, and the adjustment of the clearance on the sealing surface can be easily performed. Preferably, the actuator is provided on an opening / closing frame provided with the upper die. Thus, the opening / closing operation of the entire middle mold having the actuator can be linked with the upper mold, and work such as removal of the product from the mold can be facilitated.

Further, as a method of manufacturing a foaming mold using the foaming mold, there is the following method. That is, the upper and lower molds are provided with an opening and closing of the middle mold, and the upper and lower molds are provided with an undercut between the upper and lower molds. This is a molding method for molding a foamed resin molded article having an undercut portion in a cavity surrounded by the lower mold, the upper mold and the middle mold by using a foam molding mold for adjusting the liquid flow of the raw material on the sealing surface with the middle mold. The clearance between the upper mold and the middle mold at the sealing surface is adjusted by moving the middle mold with the actuator.
Next, there is a method for producing a foamed resin molded product, which comprises injecting a raw material into the cavity and foaming the raw material to produce the foamed resin molded product.

According to this method, it is possible to easily obtain a foamed resin molded article having no underfill or burrs in the undercut portion.

[0018]

In the foaming mold according to the present invention, the middle mold is provided with the actuator capable of moving forward and backward. Therefore, the clearance between the sealing surfaces of the upper die and the middle die can be easily maintained in an optimum state. That is, for example, prototype production is performed before mass production of foamed resin molded products starts.
By operating the actuator, the clearance between the upper mold and the lower mold is finely adjusted to an optimal state in advance. Then, the amount of operation of the actuator for making the clearance at the time of molding the foamed resin molded product into an optimum state is grasped in advance.

Next, when molding the foamed resin molded product as a product, the actuator is actuated by an optimum operation amount that has been grasped in advance so that the clearance between the sealing surfaces of the upper die and the middle die becomes an optimum value. Let it. As a result, the clearance of the sealing surface is set to an optimum state. Next, the raw material of the foamed resin molded product is injected into the cavity, and the raw material is foamed and expanded. The material that expands and expands gradually fills the cavity while degassing the gas in the cavity from the sealing surface.

At this time, the clearance of the seal surface is set to an optimum state as described above. Therefore, the liquid flow of the raw material is smoothly performed in a well-balanced manner as the expansion of the raw material progresses. Therefore, the foamed resin molded product is molded into a good shape without causing underfill or burrs even in the undercut portion.

Therefore, according to the present invention, the clearance between the upper mold and the middle mold can be easily adjusted, and the occurrence of underfill or burr in the undercut portion of the foamed resin molded product can be prevented. A foam mold can be provided.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A foaming mold according to an embodiment of the present invention will be described.
This will be described with reference to FIGS. Foaming mold 10 of this example
As shown in FIGS. 1 and 2, the upper mold 4 comprises a lower mold 3 and an upper mold 4, and the upper mold 4 is provided with the middle mold 5 so as to be openable and closable. An undercut 25 is provided between the upper mold 3 and the middle mold 5. Then, in the cavity 2 surrounded by the lower mold 3, the upper mold 4 and the middle mold 5, a foamed resin molded article 80 having an undercut portion 85 as shown in FIG. 5 is formed, and the sealing surface of the upper mold 4 is formed. The liquid flow of the raw material is adjusted between 45 and the sealing surface 54 of the middle die 5.

As shown in FIGS. 1 and 2, the middle mold 5 is provided with a retractable actuator 6 for adjusting the clearance between the sealing surfaces 45 and 54. The actuator 6 employs a pneumatic system as shown in FIGS. The actuator 6 is provided with an opening / closing frame 7 provided with the upper mold 4.
2

The air cylinder 65 is connected to a plate 67 connected to four guide poles 66, as shown in FIGS. Further, the plate 67 is fixed and connected to the middle die 5 by four connecting rods 68. The guide pole 66 is provided with the opening / closing frame 7.
The guide 661 is provided so as to be vertically movable. The air cylinder 65 is 50 mm to 12 mm.
Those having a stroke of 0 mm were selected.

The lower mold 3 is provided with a lower mold receiving base 7 as in the prior art.
3, and the lower cradle 73 further includes an airbag 75.
These components are disposed in the fixed frame 71 as a whole. In addition, the configuration of the upper mold 4 and the like are the same as in the conventional example.

Next, the operation and effect of this embodiment will be described. In the foaming mold 10 of this embodiment, the middle mold 5 is provided with an actuator 6 which can move forward and backward. Before mass-producing the foamed resin molded product 80, a trial production is performed in advance.
By operating the actuator 6, the upper mold 4 is moved.
Fine adjustment of the clearance between the mold and the middle mold 5 to an optimal state.
In this way, the optimum operation amount of the actuator 6 when molding the foamed resin molded product 80 is grasped in advance.

Next, when molding the foamed resin molded product 80 as a product, first, the sealing surfaces 45, 5 of the upper mold 4 and the middle mold 5 are formed.
The actuator 6 is actuated by the above-mentioned optimal operation amount which is grasped in advance so that the clearance of 4 becomes an optimal value. As a result, the clearance between the seal surfaces 45 and 54 is set to an optimum state.

Next, as shown in FIG.
A urethane foam raw material, which is a raw material 82 of the foamed resin molded article 80, is poured into the inside, and the opening / closing frame 72 (FIG. 1) is closed. Thereafter, as shown in FIG. 2, the airbag 75 disposed below the lower die receiving base 73 is inflated to bring the lower die 3 and the upper die 4 into contact with each other at the sealing surfaces 34 and 43, thereby providing an appropriate clearance. Set.

Next, the raw material 82 is expanded by heating. The raw material 82 spreads into the cavity 2 while degassing the gas in the cavity 2 from the sealing surfaces 34, 43, 45, 54.

At this time, the clearance between the sealing surfaces 45 and 54 is set to an optimum state as described above. Therefore, as the foaming expansion of the raw material 82 progresses, the raw material liquid flows to the undercut portion 85 smoothly in a well-balanced manner. Therefore, as shown in FIG. 5, the undercut portion 85 of the foamed resin molded product 80 is formed into a good shape without any underfill or burrs.

Therefore, according to the present embodiment, the clearance between the upper mold 4 and the middle mold 5 can be easily adjusted, and the occurrence of underfill or burrs in the undercut portion of the foamed resin molded product can be prevented. And a foaming mold can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a configuration of a foaming mold according to an embodiment.

FIG. 2 is a cross-sectional view of a foaming mold according to an example.

FIG. 3 is a plan view of a main part of the foaming mold of the embodiment.

FIG. 4 is an explanatory diagram when a raw material is injected into a foaming mold according to an example.

FIG. 5 is a sectional view of a foamed resin molded product obtained in an example.

FIG. 6 is a sectional view of a conventional foaming mold.

FIG. 7 is an explanatory view showing the configuration of a conventional foaming mold.

FIG. 8 is an explanatory view showing a state in which a raw material is foamed and expanded in a conventional example.

FIG. 9 is an explanatory diagram showing a defect in the conventional example.

FIG. 10 is a sectional perspective view of a foamed resin molded product in a conventional example.

[Explanation of symbols]

 10. . . 1. foaming mold; . . Cavity, 25. . . 2. undercut, . . Lower mold, 4. . . Medium, 5. . . Upper mold, 6. . . Actuator, 71. . . Fixed frame, 72. . . Opening / closing frame, 73. . . Lower mold cradle, 75. . . Airbag, 80. . . Foamed resin molded product, 85. . . Undercut part,

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 39/22-39/34 B29C 33/20-33/30

Claims (3)

(57) [Claims] 1. An upper mold comprising a lower mold and an upper mold, wherein the upper mold is provided with an openable / closable middle mold, and an undercut is provided between the upper mold and the middle mold. ,
A foam molding mold for molding a foamed resin molded article having an undercut portion in a cavity surrounded by an upper mold and a middle mold, and adjusting a liquid flow of a raw material on a sealing surface between the upper mold and the middle mold. A foam molding die, wherein the middle die is provided with a retractable actuator for adjusting the clearance of the sealing surface. 2. The foam molding die according to claim 1, wherein the actuator is of a pneumatic type, a hydraulic type, or an electromagnetic type. 3. The foam molding die according to claim 1, wherein the actuator is provided on an opening / closing frame provided with the upper die.