JP5454758B2 - Manufacturing method of hollow molded product - Google Patents

Description

The present invention relates to a technique for removing chips generated when a blow molded product is punched.

As a technique for removing chips generated when a blow molded product is punched, there is a technique disclosed in Patent Document 1.
JP 2007-220404 A

However, in paragraph 0012 of Patent Document 1, “when a hole is inserted into a gap in an automotive deck board formed by blow molding, a chip remains in the deck board. For the purpose of avoiding this, use a drill as described in "Using a drill with a hook at the tip and a return part at the tip of the hook ..." Since chips generated by this process still occur, the method as disclosed in Patent Document 1 has a drawback that it is impossible to prevent the generation of chips by using a drill.

The problem to be solved is to prevent the occurrence of chips by using a drill when making an insertion hole for inserting a Reinforce pipe into a gap in an automotive deck board formed by blow molding. It is a point that cannot be done. The present invention has been made to solve the above-described points.

In order to achieve the above object, the present invention is a method for producing a hollow molded article by blow molding of a thermoplastic resin, wherein a conical portion of a rod-shaped body heated to a temperature higher than the melting point of the thermoplastic resin is pressed against the hollow molded article. , Melt and soften the hollow molded product,
By pulling out the generated residue from the hollow molded product together with the rod-shaped body while adhering to the conical portion, the hollow molded product is formed.
The most important feature is that a reinforcement tube is inserted through the insertion hole and into the void in the hollow molded article .
The second main feature is that the rod-shaped body has a quadrangular cross section.

According to the present invention, when a lean force pipe is inserted into a gap in an automobile deck board formed by blow molding of a plastic resin, chips are generated by using a drill as disclosed in Patent Document 1. There is an advantage that it does not occur at all.

When inserting a lean force pipe into a gap in an automobile deck board formed by blow molding of a thermoplastic resin, it was heated above the melting point of the thermoplastic resin for the purpose of preventing generation of chips by a drill. The rod-shaped conical portion is pressed against the hollow molded article, the hollow molded article is melted and softened to break through, and through the insertion hole formed by drilling a hole in the hollow molded article, the lean in the deck board is formed. By inserting a force pipe, it was realized without sacrificing economy.

The configuration of the present invention will be described based on the embodiments of the invention as follows.

FIG. 1 is a perspective view of an automotive deck board 1 formed by blow molding of a thermoplastic resin according to an embodiment of the present invention. 2 and 2 are metallic lean-force pipes having a circular cross section inserted into the gaps in the deck board 1 from the directions of arrows A and A, and 3 and 3 are insertion holes for the lean-force pipes 2 and 2, respectively. Show.

2 to 6 are partial cross-sectional views at positions corresponding to the BB cross section of FIG. In FIG. 2, 7 is a rod-shaped body having a circular cross section, and a conical portion 8 is formed at the end of the rod-shaped body 7.

The rod-like body 7 is heated by a heating body (not shown) composed of a heating wire or the like so that the conical portion 8 is higher than the melting point of the thermoplastic resin, and the rod-like body 7 is heated to the deck board. 1 is pressed against the recess 4, and the recess 4 is melted and softened by the high heat of the conical portion 8 to break through.

At this time, a part of the recess 4 becomes a residue 12 and adheres to the conical portion 8 and is separated from the recess 4. This state is shown in FIG.

Next, when the rod-like body 7 is pulled out from the deck board 1, the residue 12 is removed from the deck board 1 together with the rod-like body 7 while being attached to the conical portion 8. Therefore, the trace from which the rod-like body 7 is removed from the deck board 1 is formed as the insertion hole 3 and remains. This state is shown in FIG.

Next, the lean force pipe 2 is inserted through the insertion hole 3 as shown in FIG.

FIG. 6 shows a state in which the lean force pipe 2 is completely inserted into the gap in the deck board 1.

In the above embodiment, a rod-like body having a circular cross section has been described as an example. However, the cross-sectional shape is not limited to this, and may be a square cross section, another polygonal cross section, or an arbitrary cross section.

Similarly, the conical portion of the rod-like body is not limited to a conical shape, and may be a quadrangular pyramid shape, another polygonal pyramid shape, or an arbitrary conical shape.

As described in the above embodiments, according to the present invention, in order to insert a reinforcement pipe into a void in an automotive deck board formed by blow molding of a thermoplastic resin, the melting point of the thermoplastic resin is exceeded. The cone-shaped portion of the heated rod-shaped body is pressed against the deck board, the deck board is melted and softened to break through, and the lean in the deck board is inserted through an insertion hole formed by drilling a hole in the deck board. Since the force pipe is inserted, there is an effect that no chips are generated by the drill.

The present invention is not limited to manufacturing a deck board with a lean force pipe for automobiles, and can be widely used for manufacturing a hollow molded article having an insertion hole for a lean force pipe .

The perspective view of the deck board for motor vehicles based on this invention Partial sectional view before inserting the rod-like body at a position corresponding to the BB cross section in FIG. Partial sectional view after insertion of the rod-like body at a position corresponding to the BB cross section in FIG. Partial sectional view after pulling out the rod-like body at a position corresponding to the BB cross section in FIG. Partial sectional view before pipe insertion at a position corresponding to the BB cross section in FIG. Partial sectional view after pipe insertion at a position corresponding to the BB cross section in FIG.

DESCRIPTION OF SYMBOLS 1 Deck board 2, 2 Lean force pipe 3, 3 Insertion hole 4 Recess 7 Rod-shaped body 8 Conical part 12 Waste

Claims (2)

A method for producing a hollow molded article by blow molding of a thermoplastic resin, wherein a conical portion of a rod-shaped body heated to a temperature higher than the melting point of the thermoplastic resin is pressed against the hollow molded article, and the hollow molded article is melted and softened. Let it break through,
By pulling out the generated residue from the hollow molded product together with the rod-shaped body while adhering to the conical portion, the hollow molded product is formed.
A method for producing a hollow molded article, comprising: inserting an insertion hole and inserting a reinforcement pipe through the insertion hole into a gap in the hollow molded article. The method for producing a hollow molded article according to claim 1, wherein the rod-like body according to claim 1 has a square cross section.