JP2003154577A - Hollow molded object made of synthetic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow molded object made of a synthetic resin capable of more enhancing the bonding strength of a pair of recessed molded objects and suppressing the deformation of the mating part of the recessed molded objects toward a hollow part. SOLUTION: This hollow molded object is obtained by joining a pair of the recessed molded objects 2a and 2b by the solidification of a molten resin through a mating process for mating the respective mating parts 3a and 3b of a pair of the recessed molded objects 2a and 2b to form a hollow flow channel 4 between the mating parts and a filling process for filling the hollow flow channel 4 with the molten resin. Further, the hollow flow channel 4 of the hollow molded object is formed from an arcuate surface 13 formed by inside mating parts 31a and 31b and expanded toward the hollow part 7 and the bent surface 15 having an almost C-shaped cross section continued to the arcuate surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin hollow molded body, and more specifically, it is possible to further improve the bonding strength of a pair of recessed molded bodies, and to hollow the abutting portion of the recessed molded body. The present invention relates to a synthetic resin hollow molded body in which deformation toward the side is suppressed.

[0002]

2. Description of the Related Art Hollow molded articles made of synthetic resin (hereinafter referred to as
It is also abbreviated as a hollow molded body. ), There is a complex shape having a predetermined thickness and a non-rotationally symmetric shape such as an intake manifold of an automobile engine. As a method for manufacturing such a hollow molded article, a pair of concave molded articles made of synthetic resin are abutted with each other to form a hollow portion and a hollow flow path is formed between the abutted portions. A method is known in which the hollow channel is filled with a molten resin and is solidified to integrally join the pair of concave shaped bodies to each other (Japanese Patent Laid-Open No. 10-18923). ). In the conventional hollow molded body manufactured in this way, the cross-sectional shape of the hollow channel is formed into a substantially rectangular shape,
While ensuring the necessary contact area between the inner peripheral surface of the hollow channel and the molten resin, the molten resin is smoothly filled and flowed in the hollow channel having a relatively simple space shape. Generation of voids inside the bonding resin formed by solidification of the is suppressed. As a result, the bonding strength between the pair of concave molded bodies is improved to some extent.

[0003]

In the conventional hollow molded article described above, when the molten resin is filled in the hollow flow path during the manufacturing process, if the molding pressure is set to a relatively large value, the molten resin is filled and flowed. Is performed more smoothly, and the joint strength between the pair of concave molded bodies can be further improved. However, when the molding pressure of the molten resin is set to a large pressure exceeding a predetermined value, as shown in FIG. 7, among the internal pressures applied perpendicularly to the inner peripheral surface of the hollow channel 104 having a substantially rectangular cross section, The inner abutting portions 131a, 131 supported in a cantilever state by the pressure component toward the hollow portion 107 side.
There is a problem that b is largely deformed toward the hollow portion 107 side, and as a result, not only the bonding strength of the pair of concave shaped bodies 102a and 102b is lowered, but also the wall shape of the hollow portion 107 is deteriorated. . From the above, the present invention is
An object of the present invention is to provide a synthetic resin hollow molded body that can further improve the bonding strength of a pair of concave molded bodies and that suppresses deformation of the abutting portion of the concave molded body toward the hollow portion. .

[0004]

According to the hollow molded article made of synthetic resin of the present invention, the abutting portions of a pair of concave molded articles made of synthetic resin are abutted to each other to form a hollow between the pair of concave molded articles. Hollow molding made by forming a part and forming a hollow flow path between each of the abutting parts, filling the hollow flow path with a molten resin, and joining the pair of concave moldings. A body, wherein each of the abutting portions, when abutting the pair of concave shaped bodies,
An inner abutting portion that abuts at a portion near the hollow portion, and an outer abutting portion that abuts at a portion away from the hollow portion, and the hollow flow path is formed by the inner abutting portion. It is characterized by being formed from an arcuate surface that bulges toward the hollow portion side and a curved surface having a substantially U-shaped cross section that is continuous with the arcuate surface. In addition, as the above-mentioned “concave molded body”, for example, a U-shaped molded body, a U-shaped molded body, and a U having a brim portion at both end edge sides.
Examples thereof include a V-shaped molded product and a U-shaped molded product having a brim portion on both end edges.

Further, each of the abutting portions may have an engaging portion which engages with each other on the abutting surface sides of the inner abutting portions when the pair of concave shaped bodies are abutted with each other. Further, at least one of the abutting portions has a protrusion on the outer surface thereof that protrudes in the abutting direction, and the protrusion causes the pair of concave shaped bodies to abut against each other and the hollow portion. The mold can be engageable with the mold when the molten resin is filled in the channel.

[0006]

EFFECTS OF THE INVENTION According to the synthetic resin hollow molding of the present invention, the hollow channel has an arcuate surface formed by the inner abutting portion and bulging toward the hollow portion side, and a substantially U-shape continuous to this arcuate surface. Since it is formed from a curved surface having a curved cross section, when a hollow channel is filled with molten resin by abutting a pair of concave molded bodies,
Even if the molding pressure of the molten resin is set to a relatively large pressure, the pressure component applied to the circular arc surface of the internal pressure applied to the inner peripheral surface of the hollow channel is dispersed in the abutting direction. In addition, the arcuate surface of the hollow flow path makes it possible to increase the rigidity of each inner abutting portion by increasing the thickness thereof toward the base portion. As a result, the joint strength of the pair of concave shaped bodies is improved, and the deformation of each inner abutting portion toward the hollow portion side is suppressed. Furthermore, if the curved surface forming the hollow channel is set to an appropriate size,
A necessary and sufficient contact area between the inner peripheral surface of the hollow channel and the molten resin can be secured, and the joint strength between the pair of concave molded bodies can be further improved. Further, if each of the abutting portions has an engaging portion, the deformation of the inner abutting portion toward the hollow portion can be further suppressed. Furthermore, if the abutting portion has a protrusion, the deformation of the inner abutting portion toward the hollow portion can be further suppressed.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to FIGS. In this embodiment, the synthetic resin hollow molded body 1 according to the present invention is used as an intake manifold to be mounted on an engine of an automobile or the like (see FIG. 4).

(1) Manufacture of Hollow Molded Body Made of Synthetic Resin As shown in FIGS. 1 and 2, the hollow molded body 1 is formed by abutting a pair of two split concave shaped bodies 2a and 2b. A hollow portion 7 is formed between the concave shaped bodies 2a and 2b. Each of the concave shaped bodies 2a and 2b has abutting portions 3a and 3b having a substantially U-shaped cross section on both edge sides along the longitudinal direction thereof.
Each of the abutting portions 3a, 3b includes an inner abutting portion 31a, 31b that abuts at a portion close to the hollow portion 7, and an outer abutting portion 32a, 32b that abuts at a portion away from the hollow portion 7. , These inner abutting portions 31a and 31b and the outer abutting portions 32a and 32b
And connecting portions 33a and 33b for connecting the two. The inner abutting portions 31a and 31b and the outer abutting portions 32a and 32b are provided between the pair of abutting portions 3a and 3b.
Further, the hollow flow path 4 is formed by the connecting portions 33a and 33b as a closed space having both ends in the flow path direction opened. The hollow resin 4 is filled with a molten resin, and the molten resin is solidified to form a bonding resin 5.
Thus, the pair of concave shaped bodies 2a and 2b are joined.

The hollow channel 4 is, as shown in FIG.
Inner abutting portions 31a and 31b in the abutting portions 3a and 3b
The arcuate surface 13 is formed by swelling toward the hollow portion 7 side, and the curved surface 15 continuous with the arcuate surface 13 is formed. The arc C forming the arc surface 13 is
It has a predetermined radius of curvature R (see FIG. 3). Due to the arcuate surface 13, the inner abutting portions 31a and 31b are thickened toward their bases. Further, the bending surface 15 has one facing surface 151 facing the arc surface 13,
It has two connecting surfaces 152 that connect the opposite end sides of the facing surface 151 and the opposite end sides of the arcuate surface 13. The two connecting surfaces 152 are chamfered 15 with respect to the facing surface 151.
3 are connected in series. As shown in FIG. 3, the cross-sectional shape of the bent surface 15 is a straight line L1 extending in the abutting direction, and straight lines L2 and L3 extending from both ends of the straight line L1 in a direction substantially orthogonal to the abutting direction. It has a substantially U shape. Therefore, the cross-sectional shape of the hollow channel is 1
One arc C and one straight line L1 facing this arc C
And a substantially D-shape surrounded by two straight lines L2 and L3 connecting both end sides of the straight line L1 and both end sides of the arc C. Further, the radius of curvature R of the arc C and each straight line L
The length dimensions of 1, L2 and L3 are set to predetermined values, and the size of the cross section of the hollow channel 4 at an arbitrary position in the channel direction is determined by the molten resin and the hollow channel 4 in the filling step. It is possible to secure a necessary and sufficient contact area with the peripheral surface.

Further, as shown in FIG. 2, a concave portion 21 (exemplified as an engaging portion) recessed in the abutting direction is formed on the abutting surface side of the inner abutting portion 31a. Further, on the abutting surface side of the inner abutting portion 31b, a convex portion 22 (exemplified as an engaging portion) that protrudes in the abutting direction and fits into the concave portion 21 is formed. Due to the engagement of the concave portion 21 and the convex portion 22 as described above, the inner abutting portion 31 is formed in the filling process.
The deformation of a and 31b toward the hollow portion 7 side is suppressed. Also,
The abutting portions 31a and 31b are connected to the connecting portions 33a and 3a.
It has a protrusion 24 protruding from the outer surface side of 3b in the abutting direction. Then, in the filling step, the engagement between the protrusion 24 and the engaging portion 26 of the molding die 25 also suppresses the deformation of the inner abutting portions 31a and 31b toward the hollow portion 7 side.

(2) Effects of the Embodiments As described above, in the hollow molded body 1 of the above embodiment, the cross-sectional shape of the hollow channel 4 is provided on the inner abutting portions 31a and 31b and is closer to the hollow portion 7 side. One arc C bulging toward one and one straight line L1 facing the arc C and extending in the abutting direction
And two straight lines L2 connecting the both ends of the straight line L1 and the two ends of the arc C and extending in a direction orthogonal to the abutting direction,
Since it is formed into a substantially D shape surrounded by L3, even if the molding pressure of the molten resin in the filling step is set to be larger than that in the conventional case, an arc surface out of the internal pressure applied to the inner peripheral surface of the hollow channel 4 is formed. The pressure component applied to 13 is dispersed in the abutting direction, and deformation of the inner abutting portions 31a and 31b toward the hollow portion 7 side is suppressed. Further, since the inner abutting portions 31a, 31b are formed thicker toward the base portion by the arcuate surface 13, the bending rigidity of the inner abutting portions 31a, 31b is improved, and the inner abutting portions 31a are improved. , 31b is further suppressed from being deformed toward the hollow portion 7 side. Further, the radius of curvature R of the arc C
The dimensions of the straight lines L1, L2, and L3 are such that the size of the cross section of the hollow channel 4 ensures a necessary and sufficient contact area between the molten resin and the inner peripheral surface of the hollow channel 4 in the filling step. It is set to an appropriate value to obtain. Therefore, compared with the conventional hollow channel whose cross-sectional shape is substantially rectangular, the molten resin filled under high pressure can be smoothly flowed in the hollow channel 4, and The joint strength between the concave molded bodies 2a and 2b is improved, and the inner abutting portions 31a and 31b are suppressed from being deformed toward the hollow portion 7 side.

Further, in the hollow molded body 1 of the above-mentioned embodiment, the cross-sectional shape of the hollow channel 4 is formed in a substantially D-shape, and the center of gravity in the cross-section is located outward. Thus, even if a void is generated near the center of gravity of the cross section of the bonding resin 5, as compared with a hollow channel in which the cross section has a substantially rectangular shape and the center of gravity of the cross section is located at the center, When the hollow molded body 1 is used, the void generation portion and the inner abutting portion 31
Since the stress concentration portions generated in a and 31b are separated from each other, the bonding strength between the pair of concave shaped bodies 2a and 2b can be improved. Further, in the hollow molded body 1 of the above-mentioned embodiment, the abutting surface side of each of the inner abutting portions 31a and 31b is
Since the concave portion 21 and the convex portion 22 that can be fitted into the concave portion 21 are respectively formed, the hollow portions of the inner abutting portions 31a and 31b are formed by fitting the concave portion 21 and the convex portion 22 in the filling step. The deformation to the 7 side is further suppressed. Further, since each of the abutting portions 3a and 3b has the protrusion 24 that can be engaged with the engaging portion 26 of the forming die 25, the engaging portion 26 and the protruding portion of the forming die 25 can be engaged in the filling step. The engagement with 24 also suppresses the deformation of the inner abutting portions 31a and 31b toward the hollow portion 7 side. Further, since the hollow flow path 4 is formed as a closed space in which only both end sides in the flow path direction are opened,
In the filling step, the molten resin is smoothly filled and fluidized in the hollow flow path 4 and solidified without contacting the mold 25 and being rapidly cooled locally. Further, since the hollow flow path 4 has a relatively simple space shape, the molten resin can be filled more smoothly. As a result, generation of voids inside the bonding resin 5 formed by solidifying the molten resin is suppressed, and a decrease in bonding strength between the pair of concave molded bodies 2a and 2b is prevented.

The present invention is not limited to the above-mentioned embodiment, but various modifications may be made within the scope of the present invention according to the purpose and application. That is, the radius of curvature R of the arcuate surface 13 and the straight lines L1, L2, L forming the curved surface 15
The length dimension of 3 can be changed within a predetermined range. Further, in the above-described embodiment, the arcuate surface is composed of one arcuate surface 13 having one curvature radius R, but the invention is not limited to this, and it may be composed of a plurality of arcuate surfaces having a plurality of curvature radii. .
In addition, in the above-described embodiment, in the bent surface 15 having a U-shaped cross section, the connecting surfaces 152 are made to be substantially orthogonal to the facing surface 151, but the present invention is not limited to this, and the connecting surface 151 and the connecting surfaces 152 are not limited to this. The inclination angle α to be formed can be set to a value smaller than 90 degrees (see FIG. 5) or can be appropriately changed to a value larger than 90 degrees. Further, in the above embodiment, in the bent surface 15 having a U-shaped cross section, the facing surface 151 and each connecting surface 152 are continuously provided via the chamfered surface 153, but the present invention is not limited to this, and the R surface is continuously provided. Alternatively, they can be arranged continuously without providing a chamfered surface or an R surface. That is, the U-shaped cross section means to include a U-shaped deformation mode. Further, in the above embodiment, each straight line L1 forming the cross-sectional shape of the bent surface 15,
L2 and L3 can be slightly changed to curves within a range considered to be a substantially straight line.

In the above embodiment, the hollow channel 4 is
Although it is configured as a closed space in which only both end sides are opened, the present invention is not limited to this, and an opening 29 through which the filled state of the molten resin can be visually confirmed may be provided in the middle of the hollow channel 4 (FIG. 6). reference). Further, in the above embodiment, each of the abutting portions 3a, 3b.
Is configured to have the engaging portion 26 and the protruding portion 24, but is not limited to this, and may be configured without providing the engaging portion 26 and the protruding portion 24 or one of them. Further, in the above-mentioned examples, the synthetic resin hollow molded body according to the present invention is exemplified as a mode in which it is applied to a molded body (intake manifold hold) including a linear portion and a curved portion, but the present invention is not limited to this. ,
The present invention can be applied to a molded product having only a linear portion (for example, an oil trainer) or a molded product having only a curved portion.

Further, various injection molding methods can be adopted as the method for producing the hollow molded body, but from the viewpoint that the above-mentioned steps can be efficiently carried out, a die slide for linearly sliding the movable die. -It is preferable to adopt an injection method or an injection molding method called a die rotary injection method in which a movable die is rotated in a plane. Examples of the above-mentioned primary and secondary molding resins include thermoplastic engineering resins such as polyamide and polybutylene terephthalate reinforced with reinforcing fibers such as glass fibers and carbon fibers. Further, as the above-mentioned primary and secondary molding resins, both may be resins of different types, but it is preferable that they are the same type of resin.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a synthetic resin hollow body according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an enlarged view of a main part of FIG.

FIG. 4 is a perspective view showing an intake manifold.

FIG. 5 is an enlarged view of a main part showing another aspect of the hollow channel.

FIG. 6 is an enlarged view of a main part showing another embodiment of the hollow molded body.

FIG. 7 is an enlarged view of a main part of a conventional hollow molded body.

[Explanation of symbols]

1: Synthetic resin hollow molded body, 2a, 2b: Recessed molded body,
3a, 3b: abutting part, 4: hollow channel, 7: hollow part, 3
1a, 31b: inner abutting portion, 32a, 32b: outer abutting portion, 13: arc surface, 15: curved surface, 21: concave portion, 22:
Convex part, 24: protrusion part, 25: mold, 26: engaging part.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Koyama             1-1, Toyota-cho, Kariya city, Aichi             Ori Co., Ltd. (72) Inventor Yamashita Yosoya             1-1, Toyota-cho, Kariya city, Aichi             Ori Co., Ltd. (72) Inventor Takamine Iwatsuki             1-1, Toyota-cho, Kariya city, Aichi             Ori Co., Ltd. F term (reference) 4F206 AA25 AA29 AB11 AD05 AD21                       AD25 AG07 AG23 AH17 JA07                       JB12 JB20 JF05 JL02                 4F211 AD05 AG07 AH16 TA04 TA08                       TC14 TD01 TD07 TN43 TN82

Claims (3)

[Claims] 1. A pair of concave moldings made of synthetic resin are abutted against each other to form a hollow portion between the pair of concave moldings, and a hollow shape is formed between the respective abutting portions. Forming a flow path,
A hollow molded body made of synthetic resin, which is obtained by filling a molten resin in the hollow channel and joining the pair of concave molded bodies, wherein each abutting portion abuts the pair of concave molded bodies. When it is made to have an inner abutting portion that abuts at a portion near the hollow portion, and an outer abutting portion that abuts at a portion away from the hollow portion, the hollow flow path includes the inner abutting portion. A hollow molded body made of synthetic resin, which is formed by an arcuate surface formed by a portion and bulging toward the hollow portion side, and a curved surface having a substantially U-shaped cross section continuous with the arcuate surface. 2. The abutting portion has an engaging portion that engages with each other on the abutting surface sides of the inner abutting portions when abutting the pair of concave shaped bodies. Hollow molded body made of synthetic resin. 3. At least one of the abutting portions has a protrusion on the outer surface thereof that protrudes in the abutting direction, and the protrusion abuts the pair of concave molded bodies. The hollow molded article made of synthetic resin according to claim 1 or 2, which is engageable with a mold for filling the hollow channel with molten resin.