JP2000117836A - Hollow resin container, method and apparatus for producing the container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strength of a welded part by a method in which a hollow resin container in which the peripheral parts of resin intermediate moldings are laid to overlap each other and welded has a projected part formed of a resin which was compressed during welding only on the container inside of the welded part. SOLUTION: When an upper jig 14 for supporting a resin intermediate molding 10 is made to approach a lower jig 16 for supporting a resin intermediate molding 12, since the tip part of the seal part 16C of the lower jig 16 and the outside of the peripheral part 14C of the upper jig 14 are arranged to overlap each other, when a joining part 10A and a joining part 12A are welded together, the compressed resin flows only inside a container as shown by an arrow W. Since a projected part 37 is formed inside the container of a welding part 35, inside the container of the welded part 35, a small burr having constriction is not generated in a root part. As a result, the strength of a welded part can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow resin container, a method for manufacturing the same, and an apparatus for manufacturing the same, and more particularly, to a hollow resin container such as a fuel tank mounted on an automobile, a method for manufacturing the same, and an apparatus for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as one method of manufacturing a hollow resin container, there is a method of integrally forming a plurality of divided resin molded articles by welding the joint surfaces of the divided resin molded articles. An example will be described below.

As shown in FIG. 10, in this method for manufacturing a hollow resin container, a hot plate 104 for melting a joint 100A of an intermediate molded article 100 and a joint 102A of an intermediate molded article 102 is formed by an intermediate molded article. An inner heating unit 106 located inside of the inner heating units 100 and 102 and a joining surface heating unit 108 that intersects the inner heating unit 106 in a T-shape. Therefore, both the joining surface 100B of the intermediate molded product 100 and the joining surface 102B of the intermediate molded product 102 are melted by the joining surface heating unit 108 of the hot plate 104, and the hot plate 104
Of the inner surface 100C of the intermediate molded product 100 adjacent to the joining surface 100C by the inner heating portion 106 of the intermediate molding 100.
And the bonding surface 10 of the inner surface 102C of the intermediate molded product 102.
After melting both the portion 102D adjacent to 2B and the portion 102D, the joining surfaces are welded to each other.

[0004]

However, in such a method for manufacturing a hollow resin container, the resin melted at the joining portion 100A of the intermediate molded product 100 and the joining portion 102A of the intermediate molded product 102 is removed by the upper jig 110. By the compression by the lower jig 112, it swells both inside and outside the container,
A small burr 120 having a constriction 118 at the base portion as shown in FIG. 11 is generated at a portion inside the container at the welding portion. As a result, the hollow resin container is easily broken starting from the burr 120, and the welding strength is reduced.

The present invention has been made in view of the above circumstances, and has as its object to provide a hollow resin container capable of improving the strength of a welded portion, a method for manufacturing the same, and an apparatus for manufacturing the same.

[0006]

According to a first aspect of the present invention, there is provided a hollow resin container in which a plurality of intermediate molded articles made of resin are overlapped and welded, and a convex formed by a resin compressed at the time of welding. It is characterized in that the portion is provided only inside the container at the welding portion.

Therefore, a convex portion formed of a resin compressed at the time of welding is formed inside the container at the welding portion, and there is no small burr having a neck at the root portion inside the container at the welding portion. As a result, since the weld does not break at the burrs, the strength of the weld can be improved.

According to a second aspect of the present invention, there is provided a method for manufacturing a hollow resin container in which peripheral portions of a plurality of resin-made intermediate molded products are overlapped and welded. Each joint is melted, and the melted resin is caused to flow only inside the container, thereby forming a convex portion only at the welded portion inside the container.

Therefore, when welding the joints of the resin layers at the time of manufacturing, by flowing the resin compressed at the time of welding only to the inside of the container, a convex portion is formed on the inside of the container at the welded portion. No small burrs with a constriction at the root are generated inside the container of the section. As a result, since the weld does not break at the burrs, the strength of the weld can be improved.

According to a third aspect of the present invention, there is provided an apparatus for manufacturing a hollow resin container in which peripheral portions of a plurality of resin-made intermediate molded products are overlapped and welded to each other. It has an upper and lower jig supporting each joint, and the upper and lower jigs are characterized in that the molten resin is shaped to flow only into the inside of the container.

Therefore, when welding the joints of the resin layers at the time of manufacturing, the resin compressed at the time of welding can be flowed only inside the container by the vertical jig. For this reason, since a convex portion is formed inside the container at the welded portion, a small burr having a neck at the root does not occur inside the container at the welded portion.
As a result, since the weld does not break at the burrs, the strength of the weld can be improved.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a hollow resin container in which a joining surface and an inner surface of each joining portion at a peripheral portion of a plurality of resin intermediate products are melted, and the joining surfaces are overlapped and welded. The method is characterized in that a temperature at which the inner surface is melted is set higher than a temperature at which the joint surface is melted.

Therefore, when welding the joints of the resin layers to each other at the time of manufacturing, the temperature at which the inner surface of each joint at the periphery of the resin-made intermediate molded product is melted becomes higher than the temperature at which the joint surface is melted. The range in which the resin on the inner surface of the welded portion is melted can be widened. As a result, since a convex portion is formed inside the container at the welded portion, small burrs having a neck at the root portion are not generated inside the container at the welded portion. Therefore, since the welded portion does not break at the burr, the strength of the welded portion can be improved.

According to a fifth aspect of the present invention, there is provided a method for manufacturing a hollow resin container in which a joint surface and an inner surface of each joint of peripheral portions of a plurality of resin-made intermediate products are melted, and the joint surfaces are overlapped and welded. The method is characterized in that a recess is formed at a boundary between a joint surface of each joint of the resin-made intermediate molded product and an inner surface.

Therefore, when welding the joints of the resin layers at the time of manufacturing, a concave portion is formed at the boundary between the joint surface of the joint and the inner surface, so that the amount of swelling of the resin on the inner surface of the welded portion is reduced. be able to. As a result, since a convex portion is formed inside the container at the welded portion, small burrs having a neck at the root portion are not generated inside the container at the welded portion. Therefore, since the welded portion does not break at the burr, the strength of the welded portion can be improved.

According to a sixth aspect of the present invention, in the method for manufacturing a hollow resin container according to the fifth aspect, a sheet material is provided on an inner peripheral surface of a plurality of resin-made intermediate molded products, and an edge of the sheet material is provided. Is extended to the concave portion.

Therefore, in addition to the contents described in claim 5, when welding the joints of the resin layers, the edge of the sheet material can be sandwiched between the joints and welded at the same time.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hollow resin container (in the present embodiment, a fuel tank for an automobile) according to a first embodiment of the present invention, a method for manufacturing the same, and a device for manufacturing the same will be described in detail with reference to FIGS.

As shown in FIG. 2, in the present embodiment, the resin intermediate molded products 10 and 1 having a concave shape and an opening peripheral portion are provided.
2 and a pair of upper jig 14 and lower jig 1 for welding press
Set to 6 respectively. In addition, the resin intermediate molded product 1
0 and 12 are each formed by injection molding or the like,
The upper intermediate molded product 10 is provided with accessory parts such as a cutoff valve 18.

As shown in FIG. 3, the cutoff valve 1
Reference numeral 8 denotes a pipe for removing gas accumulated in the upper portion of the fuel tank when fuel is supplied through an inlet pipe 22 to a fuel tank as a hollow resin container 20 including an upper intermediate molded product 10 and a lower intermediate molded product 12. And closes when the fuel rises to the valve position,
If the fuel level is below the valve position, it will be open. The gas released from the cutoff valve 18 is released to the outside through a pipe (not shown) passing through the fuel pump mounting opening 24.

As shown in FIG. 3, the sub-tank 26 and the separator 28, which are accessory parts formed on the lower intermediate molded product (the lower part of the fuel tank) 12, are integrally formed when the lower intermediate molded product is molded.

As shown in FIG. 1A, the intermediate molded product 1
0 and the joint 12A of the intermediate molded product 12 are flange portions facing each other.
Convex portions 10B and 12B are formed on the outer ends of the containers 0A and 12A, respectively, on the sides that are separated from each other, that is, toward the upper side of the paper at the joint 10A and toward the lower side of the paper at the joint 12A.

A hot plate 30 is provided between the joint 10A of the intermediate molded product 10 and the joint 12A of the intermediate molded product 12, and the hot plate 30 is used to connect the joint 10A of the intermediate molded product 10. And the joint 12A of the intermediate molded article 12 are melted. In each drawing, the molten portions of the intermediate molded products 10 and 12 are indicated by spotted hatching.

The cross section of the hot plate 30 has a T-shape and is located inside the intermediate molded products 10 and 12, and
A standing wall portions 30A and 30B for melting the inner side surfaces 10C and 12C of A and 12A, and a horizontal portion 30 where the standing wall portions 30A and 30B intersect in a T-shape to melt the joining surfaces 10D and 12D.
C. Therefore, when the hot plate 30 is heated, the intermediate part 1 is formed by the horizontal portion 30C of the hot plate 30.
Both the joining surfaces 10D and 12D of the joints 0 and 12 are melted, and the inner wall surfaces 10C and 12C of the joints 10A and 12A are melted by the standing walls 30A and 30B of the hot plate 30, respectively.

The standing walls 30A, 30B of the hot plate 30
Is set so as to be higher than the temperature of the horizontal portion 30C of the hot plate 30, so that the range of the resin to be melted can be expanded in the inner surfaces 10C and 12C of the joints 10A and 12A. I have.

Further, the joining portion 10 of the intermediate molded products 10 and 12
A, 12A joining surfaces 10D, 12D and inner surfaces 10C, 1C
At the boundary with 2C, chamfered portions 10E and 12E as concave portions
Are formed. That is, as shown in FIG. 4, a chamfered portion 10E is formed at the joint 10A of the intermediate molded product 10, and as shown in FIG.
By forming the chamfered portion 12E in 2A, as shown in FIG. 5B, the amount of resin swelling S1 on the inner surface of the welded portion 35 is increased.
However, as shown in FIG. 5A, when the chamfered portion is not formed (the shape indicated by the two-dot chain line in FIG. 4), the amount of resin swelling on the inner surface of the welded portion 35 is smaller than the amount S2 of swelling. As a result, it is possible to increase the r diameter of the periphery of the convex portion 37 formed on the inner surface of the welded portion 35 (r1> r2). As shown in FIG. 6, when the chamfered portions 10E and 12E are increased, the protrusions 37 formed on the inner surface of the welded portion 35 are not increased until a predetermined value is reached.
The radius of the periphery is increased.

As shown in FIG. 1 (A), on the outer peripheral portion of the upper jig 14, a convex portion 14A holding the vicinity of the root of the joining portion 10A of the intermediate molded product 10, and a joining portion of the intermediate molded product 10 1
A concave portion 14B for holding the convex portion 10B of the upper jig 14 is formed between the convex portion 14A and the concave portion 14B.
A gap 31 is formed between the gap and the joint 10A.

Similarly, on the outer peripheral portion of the lower jig 16, the convex portion 1 for holding the vicinity of the root portion of the joining portion 12 A of the intermediate molded product 12 is provided.
6A and a concave portion 16B for holding the convex portion 12B of the joint portion 12A of the intermediate molded product 12, and between the convex portion 16A and the concave portion 16B, between the lower jig 16 and the joint portion 16A. A gap 33 is formed.

The lower jig 16 is provided with a seal 16C on the outer side of the concave portion 16B toward the upper jig 14, and as shown in FIG. When the upper jig 14 and the lower jig 16 are brought close to each other when welding the joint 10A of the intermediate molded product 12 and the joint 10A of the intermediate molded product 12, the distal end of the seal portion 16C causes the outer peripheral portion 14C of the upper jig 14 to be welded. It is designed to overlap outside. Note that reference numeral 1 in FIG.
The gap indicated by 5 may not be provided.

Next, the operation of the present embodiment will be described.

In the present embodiment, after the joining portions 10A and 12A of the intermediate molded products 10 and 12 are completely melted by the hot plate 30, the intermediate molded product 10 and the intermediate molded product together with the upper jig 14 and the lower jig 16 are provided. The heating plate 30 is moved a predetermined distance in a direction to separate the heating plate 12 from the container 12 (in the direction of arrow A in FIG. 1A).
Pull out to. Thereafter, along with the upper jig 14 and the lower jig 16, the intermediate molded product 10 and the intermediate molded product 12 are moved in a direction of approaching (for example, the upper jig 14 is moved in a direction indicated by an arrow B in FIG. 1B). The state shown in FIG. Thereafter, the intermediate molded product 10 and the intermediate molded product 12 are further moved in a direction of approaching (for example, the upper jig 14 is moved in the direction of arrow B in FIG. 1C),
The state shown in FIG. Thereafter, as shown in FIG. 1 (D), the hollow resin container is cooled while applying an internal pressure (arrow C in FIG. 1 (D)), and then the upper jig 14 and the lower jig 1 are cooled.
6 and the hollow resin container 20 is taken out.

At this time, in this embodiment, the lower jig 16 is provided with a seal portion 16C on the outer side of the concave portion 16B toward the upper jig 14, and the compressed resin is used as shown in FIG.
As shown by the arrow W in (C), it flows only inside the container. For this reason, since the convex portion 37 is formed inside the container of the welding portion 35, a small burr having a constricted root portion does not occur inside the container of the welding portion 35. As a result, the welded portion 35 starting from the burr does not break,
The strength of the welded portion can be improved.

Further, the joining portion 10 of the intermediate molded products 10 and 12
A, 12A joining surfaces 10D, 12D and inner surfaces 10C, 1C
At the boundary with 2C, chamfered portions 10E and 12E are formed. For this reason, the inner surfaces 10 of the joints 10A and 12A
The amount of resin swelling at C and 12C can be reduced. As a result, the convex portions 3 formed on the inner side surface of the welded portion 35
The r-diameter of the seven peripheral edges can be increased. Therefore, damage from the periphery of the convex portion 37 can be reduced, and the strength of the welded portion can be further improved.

In this embodiment, the temperatures of the standing walls 30A and 30B of the hot plate 30 are set higher than the temperature of the horizontal portion 30C of the hot plate 30. For this reason, since the range of the resin to be melted inside the welded portion 35 can be expanded, the radius r of the peripheral edge of the convex portion 37 formed on the inner surface of the welded portion 35 can be increased. Therefore, damage starting from the periphery of the convex portion 37 can be reduced, and the strength of the welded portion can be further improved.

The standing walls 30A, 30B of the hot plate 30
As an example of a configuration for increasing the temperature of the hot plate 30 to be higher than the temperature of the horizontal portion 30C, as shown in FIG. 7, a configuration in which a heater 40 for exclusively heating the standing wall portions 30A and 30B of the hot plate 30 is added. Can be considered. Further, as shown in FIG. 8, far-infrared heaters 42 which are disposed in non-contact with inner side surfaces 10C and 12C instead of standing wall portions 30A and 30B of hot plate 30 are provided.
The inner surfaces 10C, 12A of the joints 10A, 12A
C may be heated. Also, the joint 10A,
In addition to the inner surfaces 10C, 12C of the 12A,
D and 12D may also be configured to be heated by a far-infrared heater.

Next, a second embodiment of the method for manufacturing a hollow resin container of the present invention will be described in detail with reference to FIGS. 9 (A) to 9 (D).

The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, as shown in FIGS. 9A to 9D, a sheet material 46 for preventing fuel leakage is provided on the inner peripheral surfaces of the intermediate molded products 10 and 12. . Further, the edge 46A of these sheet materials 46 is
0E and 12E, and the distal end portion is connected to the joining surface 1
It has reached 0D and 12D.

Therefore, in this embodiment, in addition to the operation of the first embodiment, the joining portions 10A, 10A of the intermediate molded products 10, 12
When welding 12A to each other, the edge 46A of the sheet material 46 is used.
Can be sandwiched between the joints 10A and 12A and welded at the same time, so that the assembling workability is improved.

In the above, the present invention has been described in detail with respect to a specific embodiment. However, the present invention is not limited to such an embodiment, and various other embodiments are included in the scope of the present invention. It is clear to a person skilled in the art that is possible. For example, in each of the above embodiments, the intermediate molded product 10,
The chamfers 10E, 12E as recesses are formed at the boundaries between the joint surfaces 10D, 12D of the twelve joints 10A, 12A and the inner side surfaces 10C, 12C.
Instead, the concave portion may be formed by another configuration such as an R-shaped corner. Further, in each of the above embodiments, the fuel tank of the automobile is taken as an example of the hollow resin container 20, but the hollow resin container 20 is not limited to the fuel tank of the automobile, and may be another hollow resin container. Further, in each of the above embodiments, the hollow resin container 20 is divided into the resin intermediate molded products 10 and 12, but the hollow resin container may be divided into three or more resin intermediate molded products.

[0041]

According to the first aspect of the present invention, there is provided a hollow resin container in which peripheral portions of a plurality of resin-made intermediate products are overlapped and welded, and a convex portion formed by a resin compressed at the time of welding is welded. Has an excellent effect that the strength of the welded portion can be improved.

According to a second aspect of the present invention, there is provided a method of manufacturing a hollow resin container in which peripheral portions of a plurality of resin-made intermediate molded products are overlapped and welded. By melting the joining portion and flowing the molten resin only inside the container, a convex portion is formed only on the inside of the container at the welding portion, which has an excellent effect of improving the strength of the welding portion.

According to a third aspect of the present invention, there is provided an apparatus for manufacturing a hollow resin container in which peripheral portions of a plurality of resin-made intermediate molded products are overlapped and welded, wherein each of the plurality of resin-made intermediate molded products is welded when the peripheral portions are welded. Since the upper and lower jigs have a shape that allows the molten resin to flow only inside the container, the upper and lower jigs have an excellent effect of improving the strength of the welded portion.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a hollow resin container in which a joining surface and an inner surface of each joining portion of a peripheral portion of a plurality of resin-made intermediate products are melted, and the joining surfaces are overlapped and welded. However, since the temperature at which the inner surface is melted is set higher than the temperature at which the joint surface is melted, there is an excellent effect that the strength of the welded portion can be improved.

According to a fifth aspect of the present invention, there is provided a method for manufacturing a hollow resin container in which a joining surface and an inner surface of each joining portion of peripheral portions of a plurality of resin-made intermediate products are melted, and the joining surfaces are overlapped and welded. In addition, since the concave portion is formed at the boundary between the joint surface and the inner surface of each joint portion of the resin-made intermediate molded product, there is an excellent effect that the strength of the welded portion can be improved.

According to a sixth aspect of the present invention, in the method for manufacturing a hollow resin container according to the fifth aspect, a sheet material is disposed on an inner peripheral surface of the plurality of resin-made intermediate molded products, and an edge of the sheet material is formed. Since it extends to the concave portion, in addition to the effect described in claim 5, there is an excellent effect that assemblability is improved.

[Brief description of the drawings]

1 (A) to 1 (D) are enlarged cross-sections showing a joining portion of a hollow resin container and an apparatus sequentially showing an intermediate molded article joining process of a method for manufacturing a hollow resin container according to a first embodiment of the present invention. FIG.

FIG. 2 is a cross-sectional view showing a joining portion of the hollow resin container and an apparatus, showing a state during heating in an intermediate molded article joining step of the method for manufacturing a hollow resin container according to the first embodiment of the present invention.

FIG. 3 is an exploded perspective view showing a container manufactured by the method for manufacturing a hollow resin container according to the first embodiment of the present invention.

FIG. 4 is an enlarged sectional view showing a chamfered portion of an intermediate molded product in the method for manufacturing a hollow resin container according to the first embodiment of the present invention.

FIG. 5A is an enlarged cross-sectional view showing a welded portion when a chamfered portion is not formed in the method for manufacturing a hollow resin container according to the first embodiment of the present invention, and FIG. It is an expanded sectional view showing a welding part at the time of forming a chamfer in a hollow resin container in a manufacturing method of a hollow resin container concerning an embodiment.

FIG. 6 is a graph showing the relationship between the size of the chamfer and the size of the r-diameter in the method for manufacturing a hollow resin container according to the first embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a joining portion of a hollow resin container and a heater, showing a heating state in an intermediate molded article joining step of a method for manufacturing a hollow resin container according to a modification of the first embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a joining portion of the hollow resin container and a heater during heating in an intermediate molded article joining step of the method for manufacturing a hollow resin container according to another modification of the first embodiment of the present invention. is there.

9 (A) to 9 (D) are enlarged cross-sections showing a joining portion of a hollow resin container and an apparatus sequentially showing an intermediate molded article joining process of a method for manufacturing a hollow resin container according to a second embodiment of the present invention. FIG.

FIG. 10 is a cross-sectional view showing a hollow resin container and an apparatus, showing a state during heating in an intermediate molded article joining step in a method for manufacturing a hollow resin container according to a conventional embodiment.

FIG. 11 is an enlarged cross-sectional view showing a joint portion of an intermediate molded product in an intermediate molded product joining step of a method for manufacturing a hollow resin container according to a conventional embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Resin intermediate molded article 10A Joint part of intermediate molded article 10C Inner surface of joint part 10D Joint surface of joint part 10E Chamfered part (concave part) of resin joint 12 Resin intermediate molded article 12A Joint part of intermediate molded article 12C Joint part 12D Joining surface of joining portion 12E Chamfering portion (recess) of joining portion 14 Upper jig 16 Lower jig 16C Sealing portion of lower jig 20 Hollow resin container 30 Hot plate 30A Standing wall portion of hot plate 30B Hot plate Standing wall part 30C Horizontal part of hot plate 40 Heater 42 Far infrared heater 46 Sheet material

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B29L 22:00 F term (Reference) 3D038 CA04 CC01 CC11 CC20 3E033 AA06 BA13 DA06 DA08 DB03 FA01 FA02 GA02 4F206 AD05 AD21 AD25 AG02 AG06 AG28 AH17 AH55 AM33 JA07 4F211 AD05 AD21 AD25 AG02 AG06 AG28 AH17 AH55 AM33 TA01 TA08 TC10 TC14 TD07 TH02 TH07 TH18 TJ14 TJ15 TJ22 TN07 TN28 TN87 TQ04 4F213 AD05 AD21 AD25 AG02 WA03 AM33 AG33 WE06 WE07 WK01

Claims (6)

[Claims] 1. A hollow resin container in which peripheral portions of a plurality of resin-made intermediate molded products are overlapped and welded, wherein a convex portion formed of resin compressed at the time of welding is provided only inside the container inside the welded portion. And a hollow resin container. 2. A method of manufacturing a hollow resin container in which peripheral portions of a plurality of resin-made intermediate molded products are overlapped and welded, wherein each of the joints of the plurality of resin-made intermediate molded products is melted at the time of welding the peripheral portion. A method of manufacturing a hollow resin container, wherein a molten resin is caused to flow only inside the container to form a convex portion only at the welded portion inside the container. 3. An apparatus for manufacturing a hollow resin container in which peripheral portions of a plurality of resin-made intermediate molded products are overlapped and welded, wherein the upper and lower portions support respective joints of the plurality of resin-made intermediate molded products at the time of welding the peripheral portions. An apparatus for manufacturing a hollow resin container, comprising a jig, wherein the upper and lower jigs are configured to flow molten resin only inside the container. 4. A method of manufacturing a hollow resin container in which a joining surface and an inner surface of each joining portion of a peripheral portion of a plurality of resin-made intermediate molded products are melted, and the joining surfaces are overlapped and welded. A method for manufacturing a hollow resin container, wherein a temperature for melting the side surface is set higher than a temperature for melting the joint surface. 5. A method of manufacturing a hollow resin container, wherein a joining surface and an inner surface of each joining portion of a peripheral portion of a plurality of resin-made intermediate molded products are melted, and the joining surfaces are overlapped and welded. A method for manufacturing a hollow resin container, wherein a concave portion is formed at a boundary between a joint surface of each joint portion and an inner surface of an intermediate molded product. 6. The hollow resin container according to claim 5, wherein a sheet material is provided on an inner peripheral surface of the plurality of resin-made intermediate molded products, and an edge of the sheet material is extended to the concave portion. Manufacturing method.