JP2008100444A - Method for molding resin pipe and mandrel for molding resin pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for molding a resin pipe, which smoothly molds the resin pipe while the inner face shape of the resin pipe is kept when bending processing of the resin pipe is performed, and easily pulling out a mandrel from the resin pipe after bending processing, and also to provide the mandrel for molding the resin pipe. <P>SOLUTION: At first, the resin pipe 2 consisting of a thermoplastic resin material for molding is inserted into a rod-like mandrel 1 whose surface has a definite frictional coefficient or smaller (for example, when the material is a resin such as a silicone, ≤0.08). Next, the resin pipe 2 inserted into the mandrel 1 and the mandrel 1 are bending-processed into a specified three-dimensional shape in the state where they are heated at a specified temperature (170-180°C) through a heating means not illustrated in a figure (for example, an oven or the like). Then, after this bending-processed resin pipe 2 is set in a mold 3 for molding, it is cooled by a cooling means, and in the state where the shape of the molded resin pipe 2 is stabilized (hardened), it is taken out of the mold 3 for molding. The mandrel 1 is pulled out of the molded resin pipe 2 taken out of the mold 3 to finish a molding operation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for molding a resin pipe and a mandrel for molding the resin pipe. More specifically, the resin pipe can be bent into an arbitrary three-dimensional shape, and the inner surface shape can be maintained. The present invention relates to a resin pipe molding method and a mandrel for molding the resin pipe.

  Conventionally, resin pipes used for fuel pipes and air conditioning pipes for vehicles and aircraft, or pipes for building materials are used after being processed into various bent shapes depending on the application. In order to solve problems such as unevenness of the inner surface and collapse of the inner surface shape, various inventions have been proposed for the bending method (for example, see Patent Document 1).

  When bending a resin pipe into a three-dimensional shape, there is a method of bending by using a mandrel or putting a filling in the hollow part of the resin pipe in order to prevent the inner surface from being uneven and the inner surface shape being crushed. When using a mandrel, it must be possible to easily remove the mandrel after bending the resin pipe.For this reason, the surface of the mandrel should have improved slidability such as oil and lubricant. It is necessary to apply. Further, it is necessary to have a certain hardness so that the inner surface of the resin pipe is not uneven during bending, and it is necessary to maintain the inner surface shape.

Furthermore, when bending with stuffing such as sand, it is very difficult to bend while keeping the inner surface shape and thickness constant, and it takes a lot of labor and time to put in and out the stuffing. There was a problem that the inner surface of the resin pipe after bending had to be cleaned.
JP-A-8-230029

  The present invention pays attention to such a conventional problem, and can smoothly mold the resin pipe while maintaining the shape of the inner surface of the resin pipe, and easily extract the mandrel from the resin pipe after the bending. It is an object of the present invention to provide a method for molding a resin pipe and a mandrel for molding the resin pipe.

  In order to achieve the above object, the present invention inserts a resin pipe made of a thermoplastic resin material for molding into a rod-shaped mandrel whose surface has a constant coefficient of friction or less, and the resin pipe inserted into the mandrel is inserted through a heating means. Bending into a predetermined three-dimensional shape while heating to a predetermined temperature, setting the bent resin pipe in a mold and then cooling it with cooling means, and molding the mold with a stable shape of the molded resin pipe The gist is to remove the mandrel from the molded resin pipe.

  According to another method of molding a resin pipe of the present invention, a resin pipe made of a thermoplastic resin material for molding is formed on a rod-shaped mandrel having a predetermined three-dimensional surface when heated to a predetermined temperature and having a coefficient of friction or less. The resin pipe inserted and bent into the mandrel is bent into a predetermined three-dimensional shape while being heated to a predetermined temperature via the heating means, and the bent resin pipe is cooled by the cooling means and molded. The gist is to pull out the mandrel from the resin pipe in a state where the shape of the pipe is stable.

  Further, the resin pipe molding mandrel of the present invention is a resin pipe molding mandrel for bending a resin pipe into a three-dimensional shape, and the mandrel body has a surface with a coefficient of friction or less and a JIS hardness. Is formed into a rod shape from any one of a thermoplastic resin material, a thermoplastic elastomer, and a synthetic rubber material in the range of HDD75 to 65.

  Here, the outer diameter of the mandrel body is in the range of 97 to 94 (%) with respect to the inner diameter of the resin pipe to be molded, the mandrel body is a hollow or solid rod-like body, and the mandrel It is also possible to form the main body into a hollow or solid rod-like body with a shape memory resin.

  By manufacturing a resin pipe using the mandrel as described above, the resin pipe can be bent into an arbitrary three-dimensional shape, the inner surface shape can be maintained, and a bent pipe with a better appearance can be efficiently manufactured. It is.

  Since the present invention is configured as described above, when bending a resin pipe, the resin pipe can be bent into an arbitrary three-dimensional shape, the inner surface shape can be maintained, and a bent pipe with a good appearance can be efficiently produced. The mandrel can be easily extracted from the resin pipe after being manufactured and further bent, and the productivity can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
1A to 1D are explanatory views of a manufacturing process for carrying out the resin pipe molding method of the present invention, and FIG. 2 shows a block diagram of the manufacturing process. In this embodiment, first, the surface is constant. A resin pipe 2 made of a thermoplastic resin material for molding is inserted into a rod-shaped mandrel 1 having a friction coefficient of less than (for example, 0.08 or less in the case of a resin such as silicone) (FIG. 1A). , (B) and (step (1)) in FIG. It is also possible to insert a rod-shaped mandrel 1 whose surface has a certain friction coefficient or less into a resin pipe 2 made of a thermoplastic resin material for molding.

  Next, the resin pipe 2 inserted into the mandrel 1 is bent into a predetermined three-dimensional shape in a state where the resin pipe 2 is heated to a predetermined temperature (170 ° C. to 180 ° C.) via a heating unit (not shown). (Steps (2) and (3) in FIGS. 1B and 1C and FIG. 2). Then, after the bent resin pipe 2 and the mandrel 1 are set in the mold 3, the resin pipe 2 is cooled by a cooling means (for example, blower or atmospheric temperature), and the shape of the molded resin pipe 2 is stable ( It is removed from the mold 3 by curing (FIG. 1 (c), (d) and FIG. 2 (steps (4), (5))).

  The mandrel 1 is drawn from the molded resin pipe 2 removed from the mold 3 to finish the molding operation (steps (6) and (7) in FIGS. 1 (d) and 2).

  When the mandrel 1 is pulled out from the resin pipe 2, it is possible to supply a pressurized fluid (water, air) or the like for lubrication between the resin pipe 2 and the mandrel 1.

  Next, as a second embodiment of the present invention, a shape memory resin or a shape memory alloy that becomes a predetermined three-dimensional shape when the mandrel 1 is heated to a predetermined temperature is used. In the second embodiment, as shown in FIG. 3, a resin pipe 2 made of a thermoplastic resin material for molding is inserted into a rod-shaped mandrel 1 whose surface has a constant friction coefficient or less (step (1)), The resin pipe 2 inserted into the mandrel 1 is heated to a predetermined temperature (170 ° C. to 180 ° C.) via a heating means (step (2)).

  Then, the resin pipe 2 inserted into the mandrel 1 is heated to a predetermined temperature, and the resin pipe 2 is bent into a predetermined three-dimensional shape with a three-dimensional shape stored in advance in the mandrel 1 (step (3)). The bent resin pipe 2 is cooled to a stable state (cured) by the cooling means without using a mold (step (4)), and the shape of the molded resin pipe 2 is The mandrel 1 is pulled out from the resin pipe 2 in a stable state, and the molding process is finished ((Step (5)), (Step (6))).

  By bending the resin pipe 2 into a predetermined three-dimensional shape by the molding method as described above, a predetermined shape can be bent while keeping the inner surface shape and thickness constant, and the resin pipe 2 after bending It is possible to omit the trouble of cleaning the inner surface of the resin, and the mandrel 1 can be easily pulled out from the resin pipe 2.

  In the molding method of the first embodiment, the main body of the mandrel 1 used in the molding method described above has a constant friction coefficient (for example, 0.08 when the material is a resin such as silicone) as described above. The following is a thermoplastic resin material whose JIS hardness is in the range of HDD 75-65 (the hardness of mandrel 1 is measured by a type D durometer specified in JIS K 7215-1986 (ASTM D 2240)). In addition, it is formed into a hollow or solid rod shape by any one of thermoplastic elastomer and synthetic rubber material.

  The main body of the mandrel 1 preferably has heat resistance so that it can withstand repeated molding. Moreover, the outer diameter of the main body of the mandrel 1 is set in the range of 97 to 94 (%) with respect to the inner diameter of the resin pipe 2 to be molded.

  In the molding method according to the second embodiment of the present invention, the main body of the mandrel 1 is hollowed or hollowed with a shape memory resin (for example, heat-resistant polyester, polyurethane, styrene-butadiene, polynorbornene, transpolyisoprene, etc.). What is formed into a real rod-like body is used.

  The shape memory resin can be used as a single body of the mandrel 1 or can be used in combination. Further, instead of the shape memory resin, a hollow or solid rod-shaped body may be used by using a shape memory alloy (Ni-Ti alloy, Cu alloy, Fe alloy, etc.).

  As described above, in the present invention, when the resin pipe 2 is bent, the resin pipe 2 can be bent into an arbitrary three-dimensional shape, the inner surface shape can be maintained, and a bent pipe having a good outer pipe can be efficiently produced. Can be manufactured. In addition, the mandrel 1 can be easily extracted from the resin pipe 2 after being bent, and productivity can be improved.

1A to 1D are explanatory views of a manufacturing process for carrying out the method for molding a resin pipe according to the present invention. It is a block diagram of the manufacturing process which shows 1st Embodiment of the shaping | molding method of the resin pipe of this invention. It is a block diagram of the manufacturing process which shows 2nd Embodiment of the shaping | molding method of the resin pipe of this invention.

Explanation of symbols

1 Mandrel 2 Resin pipe 3 Mold

Claims (6)

  A resin pipe made of a thermoplastic resin material for molding is inserted into a rod-shaped mandrel whose surface has a certain coefficient of friction or less, and the resin pipe inserted into the mandrel is heated to a predetermined temperature via a heating means to a predetermined tertiary. Bending into the original shape, setting the bent resin pipe in the mold and then cooling with cooling means, removing the molded resin pipe from the mold in a stable state, and molding the resin pipe A method for forming a resin pipe, characterized in that a mandrel is pulled out of a pipe.   When heated to a predetermined temperature, a resin pipe made of a thermoplastic resin material for molding is inserted into a rod-shaped mandrel whose surface having a predetermined three-dimensional shape when heated to a predetermined temperature or less, and the resin pipe inserted into the mandrel is heated by means of heating. The resin pipe is bent into a predetermined three-dimensional shape while being heated to a predetermined temperature, and the bent resin pipe is cooled by a cooling means, and the mandrel is pulled out from the resin pipe while the shape of the molded resin pipe is stable. A method for molding a resin pipe, characterized in that:   A plastic pipe molding mandrel that bends a resin pipe into a three-dimensional shape, and the mandrel body has a surface with a coefficient of friction below a certain coefficient of friction and a JIS hardness in the range of HDD75 to 65, heat A mandrel for molding a resin pipe, wherein the mandrel is formed into a rod shape from any one of a plastic elastomer and a synthetic rubber material.   The mandrel for molding a resin pipe according to claim 3, wherein an outer diameter of the mandrel body is in a range of 97 to 94 (%) with respect to an inner diameter of the resin pipe to be molded.   The mandrel for molding a resin pipe according to claim 3 or 4, wherein the mandrel body is a hollow or solid rod-shaped body.   6. The mandrel for molding a resin pipe according to claim 3, 4 or 5, wherein the mandrel body is formed into a hollow or solid rod-shaped body with a shape memory resin.

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