JPH04119808A - Manufacture of resin molded form - Google Patents

Abstract

PURPOSE:To obtain the manufacture of a resin molded form having the high mutual welding strength of pre-injection molded items and high reliability by forming a throttling section constraining a reinforced fiber flow on the upstream side of a welding section and manufacturing the pre-injection molded item with the welding section rich in a resin. CONSTITUTION:A throttling section 21 constraining reinforced fibers 20 mixed into an injection molded resin flow 19 is formed on the upstream side of the injection molded resin flow 19 of a section corresponding to the welding section 14b of a pre-injection molded item 14 in the female mold tools 11, 12. The resin 19, into which the reinforced fibers 20 injected from a resin filler hole 18 are mixed, is injected among the female mold tools 11, 12 and a male mold tool 3 one part of the reinforced fibers 20 mixed into the injection molded resin 19 is constrained by the throttling section 21 when the resin 19 reaches the throttling section 21, and the quantity of the reinforced fibers 20 reaching the welding section 14b of the pre-molded item 14 is reduced. Since the welding section 14b of the pre-injection molded item 14 is made rich in a resin, it is welded with sufficient strength, thus acquiring the resin molded form having high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing a resin molded article by injection molding a mixture of reinforcing fibers in a resin.

(Prior art) In recent years, in various industrial fields, glass fibers, carbon fibers, etc. are being mixed into resin instead of metal parts for parts that require high rigidity because they are light in weight and easy to manufacture. There is a tendency for molded products made of fiber-reinforced resin to be used.

For example, resin molded products made of fiber-reinforced resin are used for automobile parts and the like in order to reduce the weight of automobiles.

Traditionally, this type of resin molded product has been made, for example, by
A fuel distribution pipe for an automobile ennon as shown in the figure has been proposed (for example, see Japanese Patent Application Laid-Open No. 60108561).

The fuel distribution pipe 1 has a main body part 2 having a cylindrical shape with both ends closed.
The main body part 2 has a supply pipe connection part 4 to which a fuel supply pipe 3 from a fuel pump (not shown) is connected in order to introduce high-pressure fuel into the cylinders of an engine (not shown). A return pipe connection fitting 6 is provided to connect a fuel return pipe 5 for returning surplus fuel to the tank. Further, on the side wall of the main body section 2, a plurality of fuel supply lowers 7.corresponding to the intake manifolds (not shown) of each cylinder of the engine. This is provided.

The fuel distribution pipe 1 is integrally molded entirely from a synthetic resin or a synthetic resin composite material with excellent heat insulation properties.

Nylon, polyphenylene sulfide, etc. are used as the synthetic resin constituting the main body 2 of the fuel distribution pipe 1, and as a composite material, the resin is reinforced with an inorganic filler such as glass fiber or plate-shaped glue. It is used as a mixture as a material.

(Problems to be Solved by the Invention) By the way, welding, which is a joining method unique to synthetic resins, has the advantage of having a small number of parts and low joining cost.

For this reason, when attaching a pipe joint 8 as shown in FIG. 4, for example, to the fuel supply lower of the fuel distribution pipe 1 as described above, since the fuel distribution pipe 1 is made of synthetic resin,
The joint surfaces of the two are vibrated or spun to make them slide, and the heat generated at that time causes them to weld together.

However, the above-mentioned fuel distribution pipe 1 and the pipe joint 8 welded thereto require strength and rigidity when heated, so the content of reinforcing materials such as glass fibers is high.

For this reason, in the fuel distribution pipe 1 and pipe joint 8, the proportion of resin in the welded parts 7a and 8a decreases, and the reinforcing material appears on the surface of the welded parts 7a and 8a, which reduces the welding strength. There was a problem that it was small and the reliability of welding was low.

An object of the present invention is to provide a method for manufacturing a resin molded product with high weld strength and high reliability when welding a pre-injection molded part to a cow.

(Means for Solving the Problem) Therefore, the present invention provides a method for heating a pre-injection molded product obtained by injection molding a resin mixed with reinforcing fibers and another resin pre-form product at their welded parts. A method for producing a welded resin molded article, the injection molding comprising forming a constricted part for restraining the reinforcing fiber flow on the upstream side of the injection molding resin flow at a portion corresponding to the welded part of the pre-injection molded product. A preliminary injection molded product having a resin-rich welded area is manufactured by injection molding a resin mixed with reinforcing fibers using this injection molding molding tool, and a preliminary injection molded product having a resin-rich welded area is manufactured. It is characterized by thermally welding the welded portion of the resin preform.

(Function) During injection molding, the reinforcing fibers in the injection molding resin flow are restrained by the constricted portion of the injection molding tool.

Therefore, the amount of reinforcing fibers passing through the constriction section and reaching the welded section of the pre-injection molded product is reduced. This makes the welded portion rich in resin.

(Effects of the Invention) According to the present invention, reinforcing fibers in the injection molding resin flow during injection molding are restrained by the constriction part of the injection molding tool, and pass through the constriction part to the welded part of the preliminary injection molded product. As the amount of reinforcing fibers reaching the weld is reduced, the weld is rich in resin, allowing the pre-injection molded product to be welded to the weld with other resin preforms with sufficient strength to ensure reliability. It is possible to obtain high quality resin molded products.

(Example) The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an injection molding tool used in the method for producing a resin molded product according to the present invention, and FIG. 2 shows a preliminary injection molded product molded by this injection molding tool.

The injection molding tool consists of two female molding tools 11 and 12 and one male molding tool 13.

The two female mold tools 11 are female mold portions 15 that constitute portions corresponding to each half of the outer circumferential surface of the body portion 14a and the outer circumferential surface of the fledge-shaped welded portion +4b of the preliminary injection molded product 14 shown in FIG. has. Similarly, the female molding tool 12 is superimposed on the two female molding tools 11, and the outer peripheral surface of the body 14a of the pre-injection molded product 14 and the outer peripheral surface of the fledge-shaped welded part 14b are overlapped with each other. It has a female part 15 that constitutes a part corresponding to 1/2.

Further, a resin supply passage 17 that reaches each of the female mold parts 15 through a gate part 16 communicates with the two female mold tools 11 and the second female mold tool 12. The other female mold tool 12 has a resin injection port 18 for this resin supply passage 17.

On the other hand, the male mold 13 has two female molds 11 and 12.
having a male mold part 10 located in a cavity formed by said female mold part 15.15 of said pre-injection molded part 14;
constitutes a portion corresponding to the inner circumferential surface of.

Said - one female mold 11 and another female mold 12
During injection molding, the injection molding resin 19 flowing in the direction shown by arrow A in FIG. , a constricted portion 21 is formed to restrict reinforcing fibers 20 mixed in the injection molding resin flow 19.

The constricted portion 21 is also divided into a plurality of portions by molded portions 22 of ribs 23 (see FIG. 2) to prevent a decrease in strength.

Using an injection molding tool having such a structure, injection molding resin 19 mixed with reinforcing fibers 20 is poured into the resin injection port 1.
Inject from 8.

The resin 19 mixed with the reinforcing fibers 20 injected from the resin injection port 18 is applied to the female mold tools 11 and 12 and the male mold tool 13.
injected between. At the time of this injection, the injection molding resin 1
8. When reaching the constriction part 21 of the female mold tool 11.12,
The reinforcing fibers 20 mixed in the injection molding resin 19 are partially restrained by the constricted portion 21, and the amount of reinforcing fibers 20 reaching the welded portion 14b of the preform 14 is reduced.

By this injection molding, a preliminary injection molded product 14 having a resin-rich welded portion 14b is manufactured.

Similarly, another pre-injection molded product (not shown) to be heat-welded to this pre-injection molded product 14 is injection molded.

The welded part 14b of the pre-injection molded product 14 and the welded part of another pre-injection molded product (not shown) are then vibrated with ultrasonic waves or the like, or brought into contact with each other, and spin is applied to cause them to slide and heat. Weld.

In this case, the welded portion 14b of the preliminary injection molded product 14 and the welded portion of the preliminary injection molded product (not shown) are resin-rich as described above, and therefore have sufficient strength of /8
It will be worn. Thereby, a highly reliable resin molded product can be obtained.

In the above embodiment, the welded portion 14 of the pre-injection molded product 14
The other injection molded product to be welded to a may be one to which no reinforcing fibers are added.

The present invention is applicable not only to automobile parts but also to other parts.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an injection molding tool used in an embodiment of the method for manufacturing a resin molded product according to the present invention, and FIG. 2 is a preliminary drawing preformed by the injection molding tool of FIG. FIG. 3 is a perspective view of an example of a resin molded product, and FIG. 4 is an explanatory diagram of a conventional method for manufacturing a resin molded product. 1. Fuel distribution pipe, 7. Fuel supply port, 7a. Welded part. 8 Pipe joint, 8a, welded part, 10, male part 1.12,
・Female mold. 3. Male mold, 14. Preliminary injection molded product 4a body,
14b・Welding part, 15...Female part 6 Gate part, 17
Resin supply passage 8... Resin injection port, 19 Injection molded resin 20 - Reinforced fiber, 21 Squeezed part, 22 Rib molded part 23.J no. Patent Applicant Matta Patent Attorney Haka Aoyama Co., Ltd. 1 person Figure 1 Figure 4

Claims (1)

[Claims] (1) A method for producing a resin molded product by heat welding a pre-injection molded product obtained by injection molding a resin mixed with reinforcing fibers and another resin pre-form product at their welded parts. , an injection molding tool is prepared in which a constriction part for restraining the reinforcing fiber flow is formed on the upstream side of the injection molding resin flow at a portion corresponding to the welded part of the preliminary injection molded product, and this injection molding mold A pre-injection molded product having a resin-rich welded part is manufactured by injection molding a resin mixed with reinforcing fibers using a tool, and the resin-rich welded part and the welded parts of other resin preformed products are thermally welded. A method for manufacturing a resin molded product, characterized by: