JP2001170995A - Hollow formed item - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a surface appearance of both walls of a formed item at a joint portion of a plate rib which joints a pair of walls facing each other of a hollow blow-molded item. SOLUTION: The hollow blow-molded item 5 made of a thermoplastic resin has a first wall 7 and a second wall 9, both wall facing to each other, and a plate rib 11 projecting from the second wall 9 in the hollow portion 10, the top end thereof being welded to the back side of the first wall 7 wherein the top end of the plate rib 11 is intermittently welded to the back side of the first wall 7 in the lengthwise direction of the plate rib 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molded hollow molded article made of a thermoplastic resin, and more particularly to a welded portion of a plate-shaped rib of the hollow molded article.

[0002]

2. Description of the Related Art A blow molded hollow molded article made of a thermoplastic resin having ribs integrally projecting from one of a pair of opposed wall portions into a hollow portion and having a tip welded to the back surface of the other wall portion is disclosed in Japanese Unexamined Patent Publication (Kokai) No. H10-209,086. No. 3-142221, Japanese Utility Model Laid-Open No. 3-451
No. 22, for example.

[0003]

However, in the structure disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 3-142221, the tip of the plate-like reinforcing rib is welded to the back surface of the opposing wall over the entire length of the rib. For this reason, sink marks are formed on the surface of the opposed wall portion, which is not preferable in appearance.

[0004] Further, in the construction disclosed in Japanese Utility Model Laid-Open No. 3-45122, a concave rib protruding from one wall is welded to the back surface of the other wall in a dot-like manner. There is no sink mark on the surface of the wall portion, and the appearance of the other wall portion is not impaired, but the one wall portion on which the concave rib is formed is preferably disfigured by the concave rib. Absent.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide an external appearance of the surfaces of both walls at a joint portion of a rib for joining a pair of opposing walls. The goal is to improve.

[0006]

Means for Solving the Problems To solve the above-mentioned problems, a solution taken by the present invention is to solve the above problem by providing a first wall and a second wall facing each other.
And a blow molded hollow molded body made of a thermoplastic resin having a plate-shaped rib integrally projecting into the hollow portion from the second wall and having a tip welded to the back surface of the first wall. The end of the plate-like rib is intermittently welded to the back surface of the first wall along the longitudinal direction of the plate-like rib.

[0007]

According to the present invention, since the leading end of the plate-shaped rib is intermittently welded to the back surface of the first wall without being entirely welded by the above-mentioned solution, sink marks are formed on the surface of the first wall. Since the ribs that do not occur and protrude into the hollow portion from the second wall integrally have a plate shape, a large concave portion is not formed on the surface of the second wall as in the above-described conventional example, and the appearance is improved.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 3 show an embodiment in which the present invention is applied to a rear air spoiler of an automobile.

A rear air spoiler 5 as a blow molded hollow molded body made of a thermoplastic resin is attached to a trunk lid 3 of an automobile 1 by legs 5a, 5a at both ends.

The rear air spoiler 5 has an upper wall 7 as a first wall and a lower wall 9 as a second wall, and both walls 7 and 9 are curved walls at both ends in the vehicle longitudinal direction and are integral with each other. To form a hollow portion 10 inside. At approximately the center of the inner surface of the lower wall 9 in the vehicle front-rear direction, a reinforcing plate-like rib 11 extending in the vehicle width direction (longitudinal direction of the rear air spoiler 5) is integrally protruded into the hollow portion 10, and its tip is upward. It is intermittently welded to the back surface of the wall 7. That is, as shown in FIG. 2, 11a is a non-welded portion of the plate-like rib 11 with the upper wall 7, 11b is a welded portion, and the non-welded portion 11a and the welded portion 11b are in the longitudinal direction of the plate-like rib 11. Are formed alternately.

On the outer surface of the lower wall 9 corresponding to the welded portion 11b of the plate-like rib 11, a shallow recess 11c is formed in a dotted shape along the plate-like rib 11. (See FIGS. 2 and 3).

As described above, the tip of the plate-like rib 11 is
, The rigidity of the rear air spoiler 5 as a hollow molded body can be improved, and the occurrence of sink marks on the outer surface of the upper wall 7 can be prevented, thereby preventing a reduction in appearance. Since the recess 11c on the outer surface of the lower wall 9 is also small and dotted, the appearance of the lower wall 9 of the rear air spoiler 5 from below when the trunk lid 3 is opened can be suppressed.

Next, a method of forming the rear air spoiler 5 will be described with reference to FIGS.

The blow mold 20 is a split mold composed of a first mold 20a and a second mold 20b, and corresponds to a substantially central portion of the second mold 20b in the longitudinal direction of the rear air spoiler 5. A plate-like slide die 22 for forming the plate-like rib 11 is attached to the portion so as to be able to advance and retreat.

At the tip of the plate-like slide die 22, FIG.
As shown in FIG. 4, the concave portions 22a and the convex portions 22b are formed alternately, and the plate-shaped slide die 22 has the concave portion 22a formed in the cavity of the second molding die 20b as shown in FIG. It is arranged so as to be flush with the surface 20b1.

As shown in FIG. 4, the parison 2 is located between the first mold 20a and the second mold 20b of the mold 20 opened.
After the disposition of the parison 2, the molding die 20 is closed and a pressurized fluid is supplied into the parison 24 for pre-blow as shown in FIG.
4, the portion 19 serving as the lower wall 9 is projected in a plate shape, and as shown in FIG.
2b, the parison 24 is welded to the back surface of the portion 17 to be the upper wall 7. At this time, the portion 19 of the parison 24 abutting on the concave portion 22a of the plate-shaped slide die 22
Is a part 1 of the parison 24 as shown in FIG.
7, the gap S is not welded to the portion 17, and a gap S is formed between the portion 17.

Next, as shown in FIG. 7, when the plate-like slide die 22 is retracted, the parison 24 which becomes the plate-like rib 11 is formed.
2 are welded to each other by the pressure of the pressurized fluid, and FIG.
A plate-like rib 11 having a non-welded portion 11a and a welded portion 11b with respect to the upper wall 7 shown in FIG. 3 is formed. At this time, since the projection 22b of the plate-shaped slide die 22 protrudes from the cavity surface 20b1 of the second molding die 20b as shown in FIG. 7 (a), the depression 11c shown in FIGS. A point is formed on the outer surface of the wall 9.

As described above, according to the molding method of the present embodiment, the tip of the plate-like rib 11 is attached to the upper wall 7 using the plate-like slide die 22 having the recess 22a and the protrusion 22b formed at the tip.
Can be intermittently welded, so that an increase in the cost of the mold can be suppressed.

In the molding method of the present embodiment, the position of the plate-shaped slide die 22 when the plate-shaped slide die 22 is retracted is set to the plate-shaped slide die 2
The second concave portion 22a is located on the cavity surface 20b of the second mold 20b.
1, the recess 11c was formed on the outer surface of the lower wall 9 of the rear air spoiler 5. However, in order to eliminate the formation of the recess 11c, it was necessary to set The position is set to the convex portion 22 of the plate-shaped slide die 22.
It may be set so that b is flush with the cavity surface 20b1 of the second mold 20b. In this case, the recess 22 of the plate-shaped slide die 22 when the plate-shaped slide die 22 is retracted.
a is located inside the second mold 20b,
A protrusion is formed intermittently on the outer surface of the lower wall 9 of the rear air spoiler 5 corresponding to 2a along the longitudinal direction of the plate-like rib 11, and the protrusion height of the protrusion is as described above. The depth is substantially equal to the depth of the recess 11c in the embodiment.

Further, the present invention is not limited to the above rear air spoiler, but is also applicable to automobile parts such as bumpers, instrument panels, door trims, furniture, electric appliances and the like.

[Brief description of the drawings]

FIG. 1 is a rear perspective view of an automobile equipped with a rear air spoiler to which the present invention is applied.

FIG. 2 is a sectional view taken along line II-II of the rear air spoiler in FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a sectional view of a molding die of the rear air spoiler according to FIGS. 1 to 3, showing a state where the molding die is opened;

FIG. 5 is a perspective view of the plate-shaped slide type in FIG.

6A and 6B show a state in which the molding die in FIG. 4 is closed and the plate-shaped slide die is advanced, (a) is a cross-sectional view of the molding die at a convex portion of the plate-shaped slide die, and (b) is a plate-shaped slide die. It is sectional drawing of a shaping | molding die in the recessed part.

7 shows a state in which the plate-shaped slide die in FIG. 6 is retracted, wherein (a) is a cross-sectional view of a forming die corresponding to FIG. 6 (a), and (b) is a cross-sectional view of a forming die corresponding to FIG. 6 (b). .

[Explanation of symbols]

 Reference Signs List 5 rear air spoiler (hollow molded body) 7 upper wall 9 lower wall 10 hollow portion 11 plate-like rib 11a non-welded portion 11b welded portion

Continued on front page F term (reference) 4F202 AG06 AG07 AG25 AG28 AH17 AH23 AH24 AH25 AM34 CA15 CB01 CK23 CK52 4F208 AG06 AG07 AG25 AG28 AH17 AH23 AH24 AH25 AM34 LA01 LB01 LD06 LD09 LG02 LW01 LW26

Claims (1)

[Claims] 1. A heat source having a first wall and a second wall opposed to each other, and a plate-like rib integrally projecting from the second wall into a hollow portion and having a tip welded to the back surface of the first wall. A blow molded hollow molded body made of a plastic resin, wherein a tip of the plate-like rib is intermittently welded to a back surface of the first wall along a longitudinal direction of the plate-like rib. Hollow molded body.