JP2016182781A - Blow molding having insert part buried therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blow molding capable of heightening retention strength of an insert part without increasing the weight of the blow molding.SOLUTION: There is provided a blow molding into which an insert part is buried at a blow molding time. In the blow molding, the insert part is provided on a position adjacent to a folded wall part formed at the blow molding time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a blow molded article in which an insert part is embedded, and more particularly to a technique for improving the insert strength of the insert part.

  When inserting an insert part into a blow molded body, usually, the insert part is temporarily fixed in the cavity of the mold, and air is blown into the parison in a state where the melted parison is arranged in the cavity. The insert part is embedded in the blow molded body (see, for example, Patent Document 1).

JP 2014-76623 A

  The embedded insert part is held by the wall surface of the blow molded body, but the thickness of the blow molded body decreases with an increase in the blow ratio, so when the blow ratio of the part where the insert part is placed is large This inevitably causes a problem that the thickness of the blow-molded product is reduced, and the holding strength of the insert part is not sufficiently increased. In order to increase the holding strength of the insert part, it is only necessary to increase the thickness of the part holding the insert part. However, it is not easy to locally increase the thickness of the blow molded body in general blow molding. . On the other hand, when the thickness of the parison used for blow molding is increased, the thickness of the part holding the insert part increases, but in this case, the overall thickness of the blow molded body increases, and the weight of the blow molded body increases. It will increase.

  This invention is made | formed in view of such a situation, and provides the blow molded object which can raise the holding strength of insert components, without increasing the weight of a blow molded object.

  According to the present invention, there is provided a blow molded body in which an insert part is embedded at the time of blow molding, wherein the insert part is provided at a position adjacent to a folded portion formed at the time of blow molding. Is done.

  The inventor pays attention to the fact that the thickness of the blow-molded body formed at the time of blow molding is larger than the original thickness in the case where no bent meat is generated. It has been found that the holding strength of the insert part can be increased by arranging the insert part at an adjacent position, and the present invention has been completed.

Hereinafter, various embodiments of the present invention will be exemplified. The following embodiments can be combined with each other.
Preferably, the bent portion is provided so as to sandwich the insert part.

According to another aspect of the present invention, air is blown into the parison in a state in which the insert part is temporarily fixed in the cavity of the mold and the molten parison is disposed in the cavity. The mold includes a blow molding process for producing a blow molded body in which the insert part is embedded by expanding the parison, and the mold includes a first mold in which the insert part is temporarily fixed, and a first mold. A method for producing a blow-molded body, comprising: a second mold that is paired with a mold, wherein the first mold includes a bend-inducing protrusion that induces occurrence of a bend at a position adjacent to a temporary fixing position of the insert part. Is provided.
Preferably, the bend-inducing protrusions are provided in at least two places so as to sandwich the temporary fixing position.
Preferably, the first mold includes a moving part that is movable between a specified position and a retracted position that is a position retracted from the specified position at a position adjacent to the temporary fixing position, and the blow molding The process includes an initial blowing step of blowing air into the parison with the moving portion in the retracted position, and an air blowing into the parison with the moving portion in the specified position after the initial blowing step. A finishing blow process is provided.
Preferably, the bent meat induction protrusion is provided on the moving part.

The blow molded object 1 of one Embodiment of this invention is shown, (a) is a perspective view, (b) is BB sectional drawing, (c) is CC sectional drawing. It is sectional drawing corresponding to FIG.1 (c) which shows a state in case there is no fold part 7. FIG. (A) is the top view which looked at the 1st metal mold | die 8 from the cavity 12 side. (B) is sectional drawing which shows the metal mold | die 10 and the parison 18 in the cross section corresponding to the DD cross section in Fig.3 (a). (A) is sectional drawing corresponding to FIG.3 (b) for demonstrating an initial stage blow process, (b) is sectional drawing corresponding to FIG.3 (b) for demonstrating a finish blow process. is there. (A) is a top view of the temporary fixing position vicinity of the insert component 4 which shows the state by which the parison 18 was pressed on the 1st metal mold | die 8, (b) is EE sectional drawing in (a). is there. (A)-(b) is sectional drawing corresponding to FIG.5 (b), and shows the state from which the pair of bridge side walls 21s approached each other from the state of FIG.5 (b).

  Hereinafter, embodiments of the present invention will be described. Various characteristic items shown in the following embodiments can be combined with each other. The invention is established independently for each feature.

  As shown in FIG. 1A, the blow molded body 1 according to an embodiment of the present invention includes a main body portion 1 and a protruding portion 3 protruding from the main body portion 1. Since the parting line PL when forming the blow molded body 1 by blow molding is provided in the main body 1, the blow ratio is increased in the overhanging portion 3, and the wall thickness is reduced accordingly.

  An insert part 4 is embedded in the blow molded body 1 in the bottom wall 3a of the overhang portion 3 during blow molding. In the present embodiment, the insert part 4 is a hexagonal nut, but the type of the insert part 4 is not particularly limited as long as the insert part 4 has a size and shape that can be formed by a folded meat portion 7 to be described later.

  On the outer surface of the bottom wall 3 a of the overhang portion 3, a pair of substantially cylindrical recesses 5 are provided at positions adjacent to the insert component 4 so as to sandwich the insert component 4. As shown in FIG. 3, the recess 5 has a shape corresponding to a bent-thickness-inducing protrusion 15 that is provided in the first mold 8 and induces the occurrence of bent-thickness. The principle of occurrence of broken meat will be described later.

  As shown in FIGS. 1B to 1C, the bent part 7 is formed between each recessed part 5 and the insert part 4, so that the insert part 4 is sandwiched by the bent part 7. . Since the blow ratio is very large in the bottom wall 3a, the thickness of the bottom wall 3a when the folded wall portion 7 is not formed on the bottom wall 3a is small as shown in FIG. In this case, the holding strength of the insert component 4 embedded in the bottom wall 3a may be insufficient. However, in this embodiment, as shown to FIG.1 (b)-(c), the folding part 7 is formed between each recessed part 5 and the insert component 4, and the folding part 7 is formed. As a result, the thickness of the position adjacent to the insert part 4 is increased, and the holding strength of the insert part 4 is improved accordingly.

  Next, the manufacturing method of the blow molded body 1 of this embodiment and the principle of occurrence of bent meat will be described with reference to FIGS.

  The manufacturing method of the blow-molded body 1 of the present embodiment includes an insert part temporary fixing process and a blow molding process. Hereinafter, each step will be described.

(1) Insert component temporary fix process As shown in Drawing 3 (a), insert part 4 is temporarily fixed in cavity 12 of metallic mold 10 at an insert component temporary fix process. As shown in FIGS. 3A to 3B, the mold 10 includes a first mold 8 on which the insert part 4 is temporarily fixed and a second mold 9 that is paired with the first mold 8. . The insert part 4 is temporarily fixed to the first mold 8. Further, the first mold 8 includes a bend-inducing protrusion 15 that induces the occurrence of the bend at a position adjacent to the temporary fixing position of the insert part 4. As shown in FIG. 3A, the bend-inducing protrusions 15 are provided in at least two places so as to sandwich the insert part 4. The bent meat induction protrusion 15 and the insert part 4 are arranged so as to be separated along the moving direction of the parison 18. The bent thickness induction protrusion 15 may be any shape, size, and arrangement that induces the occurrence of bent meat, and is not limited to the shape, size, and arrangement shown in FIG.

  Further, the moving part 17 is provided in the first mold 8, and the bent thickness induction protrusion 15 is provided in the moving part 17. The moving unit 17 is configured to be slidable along the opening / closing direction of the mold 10. A peripheral shape of the moving unit 17 is indicated by a boundary line 16.

(2) Blow molding process The blow molding process includes a mold clamping process, an initial blowing process, and a finish blowing process.
In the mold clamping step, as shown in FIG. 3B, the melted parison 18 is placed between the first and second molds 8 and 9 with the insert part 4 temporarily fixed to the first mold 8. And the first and second molds 8 and 9 are clamped. The first and second molds 8 and 9 are provided with pinch-off portions 8 a and 9 a so as to surround the cavity 12, and the parison 18 is sandwiched between the pinch-off portions 8 a and 9 a and protrudes outside the cavity 12. Becomes the burr 18a, and the portion left in the cavity 12 is used for blow molding. Inside the cavity 12, the parison 18 has a bag shape. By blowing air into the parison 18, the parison 18 expands along the inner shape of the cavity 12.

  Next, in the initial blow process, as shown in FIG. 4A, air is blown into the parison 18 in a state where the moving portion 17 is in the retracted position, which is the position retracted from the specified position. The specified position is a position where the inner surface shape of the cavity 12 becomes a shape along the outer surface shape of the blow molded body 1 as shown in FIG. When air is blown into the parison 18 with the moving portion 17 in the retracted position, the parison 18 expands to the inner surface position of the moving portion 17 in the retracted position, as shown in FIG.

  Next, in the finish blow process, as shown in FIG. 4B, air is blown into the parison 18 in a state where the moving portion 17 is in the specified position. At this time, a crease occurs between each crease-inducing protrusion 15 and the insert part 4 to form the crease 7.

Here, an example of the principle of occurrence of bent meat will be described with reference to FIGS.
When air is blown into the parison 18 in a state where the moving portion 17 is in the specified position, the parison 18 is pressed against the inner surfaces of the first mold 8 and the moving portion 17. Ideally, the parison 18 is deformed into a shape along the shape of the inner surface of the cavity 12, but when the insert part 4 and the fold-inducing protrusion 15 are adjacent to each other, the space between the insert part 4 and the protrusion 15 is not in the parison. As a result, as shown in FIGS. 5A to 5B, the parison 18 is deformed so as to cover the whole of the insert part 4 and the protrusion 15, so that the gap between the insert part 4 and the protrusion 15 is reduced. A bridge 21 is formed. The bridge 21 includes a bridge side wall 21 s that connects the side surfaces of the insert part 4 and the protrusion 15, and a bridge upper wall 21 t that connects the top surfaces of the insert part 4 and the protrusion 15.

  When the bridge upper wall 21t is deformed so as to be pressed against the inner surfaces of the first mold 8 and the moving part 17 from the state of FIGS. 5A to 5B, no bent meat is generated, but as shown in FIG. When the pair of bridge side walls 21s is deformed so that the distance between the pair of bridge side walls 21s is narrowed, finally, as shown in FIG.

  The deformation of the bridge side wall 21s as shown in FIGS. 6A to 6B is particularly likely to occur when the parison 18 has a bump (slack). In the present embodiment, since the parison 18 is greatly expanded in the initial blow process and then the moving portion 17 is moved to a specified position, the parison 18 is bumped in the vicinity of the moving portion 17. Is easily formed. In addition, since it is possible to generate bent meat without performing the initial blow process by devising the shape and arrangement of the bent thickness induction protrusions 15, the initial blow process is not necessarily required. Further, when the initial blow process is not performed, the moving unit 17 is not necessary.

  After the finish blow step, the mold 10 is opened, the blow molded body 1 is taken out, and the burr 18a is removed. In the blow molded body 1, a recess 5 is formed at a position corresponding to the bent meat induction protrusion 15. Further, a region A in FIG. 1A is a region corresponding to the inner surface of the moving unit 17.

1: blow molded body, 2: main body part, 3: overhang part, 4: insert part, 5: recessed part, 7: folded part, 8: first mold, 9: second mold, 10: mold, 12: Cavity, 15: Fracture induced protrusion, 16: Boundary line, 17: Moving part, 18: Parison, 21: Bridge, 21s: Bridge side wall, 21t: Bridge upper wall

Claims (6)

A blow molded body in which insert parts are embedded at the time of blow molding,
The insert part is a blow molded body provided at a position adjacent to a folded portion formed during the blow molding. The blow molded body according to claim 1, wherein the bent meat portion is provided so as to sandwich the insert part. Insert part temporary fixing process for temporarily fixing the insert part in the cavity of the mold,
In a state where the melted parison is disposed in the cavity, a blow molding process for producing a blow molded body in which the insert part is embedded by blowing air into the parison and expanding the parison,
The mold includes a first mold on which the insert part is temporarily fixed, and a second mold that is paired with the first mold.
A 1st metal mold | die is a manufacturing method of a blow molded object provided with the folding-thickness induction protrusion which induces generation | occurrence | production of folding thickness in the position adjacent to the temporary fix | stop position of the said insert components. The method according to claim 3, wherein the bend-inducing protrusions are provided in at least two places so as to sandwich the temporary fixing position. The first mold is provided with a moving portion that is movable between a specified position and a retracted position that is a position retracted from the specified position at a position adjacent to the temporary fixing position,
The blow molding step includes an initial blowing step of blowing air into the parison with the moving portion being in the retracted position, and an inner portion of the parison with the moving portion being at the specified position after the initial blowing step. The method of Claim 3 or Claim 4 provided with the finish blow process which blows in air. The method according to claim 5, wherein the bent meat induction protrusion is provided on the moving part.