JPS62218117A - Method of molding plastic hollow body - Google Patents

Abstract

PURPOSE:To prevent preformed items form deforming and shifting during postforming by a method wherein abutting projections support the parts, which float in a cavity, of the preformed items. CONSTITUTION:At the preforming of a right half pipe 1 and a left half pipe 2, abutting projections 3 are integrally molded with the half pipes so as to abut against the inner surface of a cavity when the half pipes are set in a mold for postforming in such discontinuous manners that the respective projections 3 of the half pipe 2 locate alternately between the respective projections 3 of the half pipe 1 as for flanges 13 and 23 and the abutting projections 3 of flanges 11 and 21 locate on their front and back surfaces and tip surfaces. The respective half pipes 1 and 2 are fitted in the mold so as to set in the state that the respective abutting projections 3 abut against the inner surface of the mold cavity in order to prevent the half pipes from deforming and shifting. Then, after the mold is clamped, glass fiber reinforced nylon is injected in the cavity for molding so as to form a molding layer B1 at the heads of the flanges 13 and 23 and molding layers onto the flanges 11 and 21 in such a manner that the respective abutting projections 3 are integrally molded so as to be imbedded flush with the respective layers.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention can be used, for example, in intake pipes of automobile engines, etc. The present invention relates to a method of manufacturing a plastic hollow body having a complicated shape, and is used in the field of plastic molding and processing.

[Conventional technology]

As a manufacturing method for plastic hollow bodies with complex shapes that change three-dimensionally, such as intake pipes used in automobile engines, the hollow body is divided into two parts, and products of each divided shape are formed by preforming. A method has been developed in which the parts are placed in their respective molds, the molds are tightened, and the outer skin is post-molded (injection molded) to cover the joints.
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[Problem that the invention seeks to solve]

However, in the above-mentioned molding method, the preformed parts made of Shiku plastics set in the mold are deformed or misaligned due to injection pressure and resin flow during post-molding (injection molding).
This caused deformation of the product and eccentricity of the insert body.

That is, for example, the intake pipes 1, 2A, 2B, etc.
．． 2? After dividing and preforming, both preforms were set in 1.2ft molds and held in the state shown in Figure 2A in the molds, and then postformed so as to cover the overlay flanges 13 and 231 of each. The build-up B, ft@5B is applied as shown in the figure, but the flanges 13 and 23 are deformed due to the injection pressure of several hundred ky/ctl and the flow pressure of the resin during post-molding, and the preformed product 1, As a result of the final product being molded in a constant state due to misalignment or deformation between the insert bodies 1 and 2, the airtightness and bonding force between the insert bodies 1 and 2 may be reduced, and there is a risk that the hollow body 1, for example, as a conduit, may be disturbed by the flow of fluid. 〇 [Measures and actions to solve the problem] The present invention is designed to eliminate the gap that becomes the resin filling part when the preform is set in the mold for post-forming during the preforming process. Place the preform inside the VC.

The protrusions that come into contact with the inner surface of the cavity are discontinuously integrally molded, and during post-molding, the contact protrusions of each preform are set in the mold so that they act as a branch inside the cavity, and then Each preformed product is integrated by injection molding.

That is, as shown in Figure I5, 2C23, when forming the right half and left half preforms 1.2,
．． The abutting protrusions 3 are discontinuously disposed at appropriate locations on the flange 11, 23, and the abutting protrusions 3 are integrally molded on the front and back surfaces of the flange 11. Each preform 1
．． 2'! ! -1 Each abutment protrusion 3 is set as if it were a support column, tightened, and injection molded as post-molding to solve the conventional problems.0 During post-molding, The part of the preform located inside the cavity is affected by the injection pressure and the wood flow, but as shown in Fig. M3C, the abutment protrusion 3 comes into contact with the cavity inner surface [fi and plays the role of a support, so it is not used for overlay. This prevents the flanges 13.23 from deflecting, and each of the seven flanges 11.21 is floating in the cavity because the entire circumference is integrated with the overlay by post-forming. The protrusions 3 of the respective flanges 11 .
Did you prevent the 21 pains? [Example] As is clear from Figs. 1 to 13, the intake pipe of an engine having a three-dimensionally deformed shape was preformed separately as a right half pipe 1 and a left half pipe 2, and each half pipe was preformed. In this case, a head flange 13.23 for build-up on the upper and lower joints of each half-pipe part is placed between each protrusion 3 of the half-pipe l so that it will come into contact with the inner surface of the cavity when set in the mold for post-forming. Each protrusion 3 of the half-vibrator 2 is discontinuously positioned, and each contact protrusion 3 is integrally molded discontinuously on the surface and tip surface of the flange 11.21KFi for each installation. o Each half pipe 1.2 of the intake pipe is made of glass fiber-reinforced nylon 6't-molded with a general wall thickness of 3 sm+.Next, each half pipe 1.2 obtained is fitted into a mold for each half, and each The contact protrusion 3 is set in contact with the inner surface of the mold cavity, tightened, and glass fiber reinforced nylon 66 is injection molded.
Overlay 7 langes 13, 2 forming pipe body joints
Molded NBl on the head of 3? For installation, use a half flange 11.
For 21, molding mB, 'p, abutting protrusion 3, respectively.
In this embodiment, both ends of each pipe body are attached to the flanges 11 and 21U during post-molding, regardless of whether they are floating in the cavity. Since the abutting protrusion 3 and the abutting protrusion 3 on the front surface of the image are partially supported by the capitivity surface, there is no problem even under the action of an injection pressure of several hundred kg/ctl. The mouth was able to prevent deformation and movement to the extent that it would occur! The contact protrusion 3 provided with each padded instep flange 13°23Vc is also
As with the protrusion 3 on the flange, the head of each built-up flange 13.23 is suitably integrated to create an intake vibe with uniform mechanical properties without causing any deformation or eccentricity in the conduit section. In addition, since compatible glass fiber reinforced plastics were used for the pre-formed material and the post-formed material, a strong and homogeneous intake vibe was obtained.

In addition, at the appropriate place on the joining surface of the half pipes 1 and 2, there is a fitting part Jt with an undercut shape as shown in the 2D diagram. After the two pipe bodies 1.2 were joined together, the mold was set.1 The work efficiency was improved.

When implementing the present invention, the shape of the part, the combination of the preformed material and the postformed material, the shape and arrangement of the contact protrusions, etc. can be selected and applied as necessary. [Effect of the invention] Is the abutting protrusion a floating part in the cavity of the preformed product? Because it is supported, it is possible to prevent the insert body (preformed product) from deforming or shifting during post-molding.

By distributing the abutting protrusions in a discontinuous manner, support for the insert body can be achieved with fewer protrusions and can be integrated without interfering with resin flow during post-molding. In addition, the physical characteristics of the protrusions occupying the post-forming layers B, B, are small, and the mechanical properties of the post-forming layer are not deteriorated.

[Brief explanation of drawings]

FIG. 1 is a plane M showing the combined state of the preformed parts of the present invention. Fig. 2A is a cross-sectional view taken along line XX in Fig. 11, a partial enlarged view of the build-up flange in Fig. 2B and g2A, and Fig. 2C.
The figure is @2B2B on the Y-Y line of Army 1 figure, and! 2
Figure D is an improved example corresponding to Figure 2B. Figure 3 is a side view showing the assembled state of the preformed product of the present invention. Figure 4 is a plan view of the final product; Figure 5A is a sectional view corresponding to Figure 1EZA of the final product; Figure 5B is a sectional view of the final product corresponding to Figure 112B. And 1. Figure Ir5C is a sectional view of the final product corresponding to Figure 2C, and Figure 6 is a side view of the final product corresponding to Figure 3. 1: Right side half pipe, 2: Right side half pipe, 3: Contact projection % 11, 21: Mounting on companion half flange, 13.23: Overlay flange, 1o: Conduit - Figure 1 1 - Right half Pipe 2 - One right side half pipe 3 - Contact projection 10 - One pipe line 11.21 - m - Mounted on the companion half flange 13.23 - One built-up 111 flange F - m - Mounted on the third flange Figure 4 Figure 5B Figure 50 WJG diagram procedural amendment (method) June 1985 Director General of the Japan Patent Office Mr. Michibe Uga 1, Indication of the case 1985 Patent Application No. 060948 2, Invention Name: Molding method for plastic hollow bodies 3, relationship with the amended case Patent applicant name: Toyoda Gosei Co., Ltd. 4, agent address: 8-10-5, Toranomon-chome, Minato-ku, Tokyo 105
Date of amendment order (shipment date) 6. In column 7 of "Detailed description of the invention" of the specification subject to amendment, above [Industrial field of application] on page 1, line 12 of the specification of contents of amendment,
Add the item "3. Detailed description of the invention".

Claims (1)

[Claims] 1. At the time of preforming, the abutting protrusions (3) are integrally molded in a discontinuous configuration at appropriate locations, and then each abutting protrusion (3) is brought into contact with the cavity surface in the post-forming mold to perform preforming. A method for molding a hollow plastic body, which comprises setting the products (1, 2) in a mold and post-molding them so as to cover the joints.