JP7217584B2 - blow molding - Google Patents

Description

The present invention relates to blow molded articles. More particularly, it relates to a hollow blow-molded article obtained by blow-molding a resin parison.

BACKGROUND ART Conventionally, a blow-molded article formed by blow-molding a resin parison is known (see, for example, Patent Document 1). The blow-molded body in Patent Document 1 is a lid that constitutes a glove box, and includes a pair of front and back walls separated from each other in the thickness direction. In addition, in order to improve the rigidity of the lid, recesses having a U-shaped cross section are formed in the front wall and the back wall, and the bottoms of the recesses are brought into contact with each other. Note that the lid is a flat plate extending in a plane.

Japanese Patent Publication No. 2007-504037

However, in the case where the lid is formed to be curved in an arc shape when viewed from the side, if a concave portion is formed in the front wall arranged on the outer peripheral side (convex side) toward the back wall side, the concave portion is formed in the flat plate lid. The stretch ratio of the parison in the concave portion is increased as compared with the case where it is formed. Therefore, there is a problem that the plate thickness of the concave portion becomes thin during blow molding.

In order to solve the above-described problems, the present invention provides a method for blow molding in the vicinity of a connecting portion that connects respective concave portions formed in a part of a pair of wall surfaces that are curved in an arc shape when viewed from the side. To provide a blow-molded article capable of suppressing thinning caused by stretching of a part.

In order to solve the above-described problems, a blow-molded article according to the present invention has at least a portion thereof curved in an arc shape when viewed from the side, and is arranged on the outer peripheral side in a cross section along the arcuately curved circumferential direction. and an inner peripheral wall spaced from the outer peripheral wall on the inner peripheral side in the thickness direction of the outer peripheral wall. The outer peripheral wall and the inner peripheral wall are partly joined via a joining portion, and the joining portion is arranged on the outer peripheral side of the center in the thickness direction of the outer peripheral wall and the inner peripheral wall facing the outer peripheral wall. In a portion of the outer peripheral wall that is curved in an arc when viewed from the side, an outer peripheral wall side concave portion is formed in the vicinity of the coupling portion and is recessed toward the inner peripheral side. Inner peripheral wall side recesses that are recessed toward the outer peripheral side are formed in the arcuately curved portions near the joint portions, and the bottoms of the outer peripheral wall side recesses and the bottom portions of the inner peripheral wall side recesses are joined to form the joint. The maximum value of the inner peripheral wall side length along the circumferential direction of the inner peripheral wall side recessed portion is larger than the maximum value of the outer peripheral wall side length of the outer peripheral wall side recessed portion along the circumferential direction.

In the vicinity of the connecting portion of the arc-curved blow-molded body, there is a problem that the bent portion of the outer peripheral wall is stretched during the blow molding and the plate thickness becomes thin. Here, in the vicinity of the connecting portion, the elongation rate at which the bent portion of the outer peripheral wall is stretched during blow molding is different when the connecting portion is arranged on the inner peripheral side than the center in the thickness direction of the outer peripheral wall and the inner peripheral wall. In comparison with the case where the coupling portion is arranged on the outer peripheral side of the thickness direction center of the outer peripheral wall and the inner peripheral wall, the coupling portion is arranged on the outer peripheral side of the thickness direction center of the outer peripheral wall and the inner peripheral wall. The stretch ratio of the bent portion of the outer peripheral wall is smaller in the case where the outer peripheral wall is bent. Therefore, in the vicinity of the connecting portion, it is suppressed that the bent portion of the outer peripheral wall is stretched during blow molding and the plate thickness is reduced.

It is a perspective view showing a glove box concerning an embodiment of the present invention. FIG. 2 is a perspective view showing a load absorbing member arranged inside the lid of the glove box of FIG. 1; FIG. 3 is a cross-sectional view taken along line AA of FIG. 2; FIG. 4 is an enlarged cross-sectional view of a main part of FIG. 3; FIG. 2 is a cross-sectional view taken along line BB of FIG. 1; FIG. 3 is a cross-sectional view of the initial stages of blow molding the lid of the glove box; FIG. 10 is a cross-sectional view of a later stage of blow molding the lid of the glove box;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In the drawings, FR indicates the front side of the vehicle, RR indicates the rear side, RH indicates the right side in the vehicle width direction, and LH indicates the left side in the vehicle width direction.

As shown in FIG. 1, an instrument panel (not shown) is arranged in the front part of the passenger compartment of an automobile. A glove box 1 shown in FIG. 1 is arranged on the passenger seat side, which is the left side (LH side) in the vehicle width direction of the instrument panel. The glove box 1 is integrally formed of a resin from a lid 3 arranged on the inside of the vehicle compartment, which is the rear side of the vehicle, and a housing portion 5 arranged on the outside of the vehicle compartment, which is the front side of the vehicle. In this embodiment, the glove box 1 is accommodated in the accommodation portion of the instrument panel, and the lid 3 extends along the vertical direction.

The lid 3 is a plate-shaped member made of resin, and is curved in an arc shape when viewed from the side of the vehicle. Specifically, as shown in FIGS. 1 and 5, the lid 3 is composed of a lid body 7 and a load absorbing member 9 (blow-molded body) disposed inside the lid body 7 .

The housing portion 5 includes a pair of left and right side surfaces 11, 11 formed in a triangular shape that tapers downward, a front surface 13 that connects front edges of the pair of side surfaces 11, 11 along the vehicle width direction, and a front surface. 13 and a bottom surface 15 arranged below the side surfaces 11, 11. The rear edges of the pair of side surfaces 11 , 11 are joined to the back surface of the lid 3 . A rotating shaft 17 projecting laterally is provided at the lower portion of the side surfaces 11, 11, and the glove box 1 is configured to be openable (rotatable) in the front-rear direction around the rotating shaft 17. there is A stopper 19 is provided on the upper portion of the side surface 11 .

As shown in FIGS. 2 to 5, like the lid 3, the load absorbing member 9 (blow molded body) is formed in a flat shape curved in an arc when viewed from the side of the vehicle. Specifically, the outer peripheral wall 21 is arranged on the vehicle rear side (outer peripheral side, vehicle interior side), and the outer peripheral wall 21 is arranged apart from the vehicle front side (inner peripheral side, thickness direction inner side, vehicle interior side). and a curved inner peripheral wall 23, which is convexly curved toward the rear side of the vehicle. An extending portion 25 extending upward is formed on the upper portion of the right side in the vehicle width direction of the load absorbing member 9, and a tongue 27 is provided on the upper end of the left side in the vehicle width direction. is fixed to the lid body 7.

As shown in FIGS. 2 and 3, the outer peripheral wall 21 is formed integrally with a wall main body portion 31 and an outer peripheral wall recessed portion 33 recessed toward the vehicle front side. The outer peripheral wall side recessed portion 33 includes a bottom portion 35 and a side portion 37 obliquely extending from the peripheral edge of the bottom portion 35 toward the vehicle rear side (outer peripheral side) while increasing in diameter. The side portion 37 is shaped like a side surface of a truncated cone.

The inner peripheral wall 23 is formed integrally with a wall main body portion 39 and an inner peripheral wall recessed portion 41 recessed toward the rear side of the vehicle. The inner peripheral wall side recessed portion 41 is composed of a bottom portion 43 and a side portion 45 obliquely extending from the peripheral edge of the bottom portion 43 toward the vehicle front side (inner peripheral side) while increasing in diameter. The side portion 45 is shaped like a side surface of a truncated cone.

Here, as shown in FIGS. 3 and 4, in the inner peripheral wall side recessed portion 41, the bottom portion 43 extends along the extending direction of the inner peripheral wall 23 (surface direction of the inner peripheral wall 23, circumferential direction of the inner peripheral wall 23, vertical direction). is W0, and the inner peripheral wall side length at the front end of the side portion 45 is W1. Since the side surface portion 45 extends obliquely toward the front side of the vehicle, the inner peripheral wall side length of the inner peripheral wall side recessed portion 41 is set to a minimum value of W0 and a maximum value of W1.

In the outer peripheral wall side recessed portion 33, the length of the bottom portion 35 along the extending direction of the outer peripheral wall 21 (surface direction of the outer peripheral wall 21, circumferential direction of the outer peripheral wall 21, vertical direction) is W0, and the length of the side portion 37 is W0. The outer peripheral wall side length at the rear end is W2. Since the side surface portion 37 extends obliquely toward the rear side of the vehicle, the outer peripheral wall side recessed portion 33 has a minimum length of W0 and a maximum length of W2. The magnitude relationship among W0, W1, and W2 is set to W0<W2<W1. Thus, the maximum length of the inner wall side recess 41 along the circumferential direction is greater than the maximum length of the outer wall side recess 33 along the circumferential direction.

Further, as shown in FIG. 3 , the bottom portion 35 of the outer peripheral wall side recessed portion 33 and the bottom portion 43 of the inner peripheral wall side recessed portion 41 are integrally joined to form a joint portion 47 . As a result, the outer peripheral wall 21 and the inner peripheral wall 23 are partly joined via the joining portion 47 , and a hollow portion 49 is formed between the outer peripheral wall 21 and the inner peripheral wall 23 . A center CL1 (thickness direction center) between the outer peripheral wall 21 and the inner peripheral wall 23 facing the outer peripheral wall 21 and a radial center C1 of the coupling portion 47 are indicated by dashed lines. The coupling portion 47 is arranged on the rear side of the vehicle (on the outer peripheral wall 21 side, on the outer peripheral side) of the separation direction center CL1 (thickness direction center). In FIG. 4, the side surface portion 45A of the inner peripheral wall side recessed portion 41 indicated by a chain double-dashed line shows another embodiment in which the side surface portion 45A extends toward the vehicle front side in a cylindrical shape with substantially the same diameter. The cross-sectional length of the side surface portion 45A of the inner peripheral wall recessed portion 41 according to another embodiment is set longer than the cross-sectional length of the side surface portion 45 according to this embodiment indicated by the solid line.

Next, the procedure for molding the load absorbing member 9 (blow molded body) will be described with reference to FIGS.

First, a mold 51 to be used is composed of a core mold 53 arranged on the lower side of FIG. 6 and a cavity mold 55 arranged on the upper side. A molding surface 57 of the core die 53 is formed with a core-side protrusion 59 that protrudes upward (toward the cavity die). On the other hand, a molding surface 61 of the cavity mold 55 is formed with a cavity-side projection 63 projecting downward (toward the core mold). These core-side protrusions 59 and cavity-side protrusions 63 are arranged at opposing positions. The height of the core-side protrusion 59 is set larger than the height of the cavity-side protrusion 63 .

Air is blown into the cylindrical parison to expand it, and the parison is placed on the forming surface 57 of the core mold 53 with the outer peripheral wall 21 and the inner peripheral wall 23 separated from each other. As shown in FIG. 6, when the core mold 53 rises and the cavity mold 55 descends, the core-side protrusion 59 and the cavity-side protrusion 63 approach each other.

Next, as shown in FIG. 7, the core die 53 is placed at the top dead center, the cavity die 55 is placed at the bottom dead center, and air is further blown into the parison. Then, the outer peripheral wall 21 is pressed against the molding surface 61 of the cavity mold 55, the inner peripheral wall 23 is pressed against the molding surface 57 of the core mold 53, and a part of the outer peripheral wall 21 is pressed downward by the cavity-side protrusion 63. , part of the inner peripheral wall 23 is pressed upward by the core die 53 . As a result, an outer peripheral wall recess 33 recessed toward the inner peripheral side is formed in the outer peripheral wall 21, and an inner peripheral wall recess 41 recessed toward the outer peripheral side is formed in the inner peripheral wall 23, and these recesses are formed on the outer peripheral wall side. The bottom portion 35 of 33 and the bottom portion 43 of the inner peripheral wall side recessed portion 41 are integrally connected to form a connecting portion 47 .

The effects of this embodiment will be described below.

(1) The load absorbing member 9 (blow-molded body) according to the present embodiment is at least partially curved in an arc shape when viewed from the side, and is arranged on the outer peripheral side in a cross section along the arc curve in the circumferential direction. It is a flat blow-molded body in which a hollow portion 49 is formed between an outer peripheral wall 21 and an inner peripheral wall 23 spaced from the outer peripheral wall 21 on the inner peripheral side in the thickness direction. The outer peripheral wall 21 and the inner peripheral wall 23 are joined at the bottoms 35 and 43 (parts) via a joining portion 47, and the thickness direction center of the outer peripheral wall 21 and the inner peripheral wall 23 facing the outer peripheral wall 21 A coupling portion 47 is arranged on the outer peripheral side of CL1.

In the vicinity of the coupling portion 47 of the load absorbing member 9 (blow molded body) curved in an arc, there is a problem that the bent portion of the outer peripheral wall 21 is stretched during blow molding and the plate thickness becomes thin. Here, in the vicinity of the connecting portion 47, the elongation rate at which the bent portion of the outer peripheral wall 21 is stretched during blow molding is determined so that the connecting portion 47 is located on the inner peripheral side of the center CL1 in the thickness direction between the outer peripheral wall 21 and the inner peripheral wall 23. is arranged and the joint portion 47 is arranged on the outer peripheral side of the center CL1 in the thickness direction between the outer peripheral wall 21 and the inner peripheral wall 23, the thickness of the outer peripheral wall 21 and the inner peripheral wall 23 is The stretch ratio of the bent portion of the outer peripheral wall 21 is smaller when the coupling portion 47 is arranged on the outer peripheral side of the direction center CL1. Therefore, in the vicinity of the connecting portion 47, it is suppressed that the bent portion of the outer peripheral wall 21 is stretched during blow molding and the thickness of the outer peripheral wall 21 is reduced.

(2) In the vicinity of the coupling portion 47, the outer peripheral wall 21 is formed with an outer peripheral wall side recess 33 recessed toward the inner peripheral side, and the inner peripheral wall 23 is formed with an inner peripheral wall side recess 41 recessed toward the outer peripheral side. , and the bottom portion 35 of the outer peripheral wall side recessed portion 33 and the bottom portion 43 of the inner peripheral wall side recessed portion 41 are coupled to form a coupling portion 47 . The maximum value W1 of the inner peripheral wall side length along the circumferential direction of the inner peripheral wall side recessed portion 41 is larger than the maximum value W2 of the outer peripheral wall side length of the outer peripheral wall side recessed portion 33 along the circumferential direction.

Also in the inner peripheral wall side concave portion 41, there is a problem that the bent portion of the inner peripheral wall 23 is stretched during blow molding and the plate thickness becomes thin. Here, the maximum value W1 of the inner peripheral wall side length is larger than the maximum value W2 of the outer peripheral wall side length. Therefore, in the inner peripheral wall side concave portion 41, the elongation rate at which the bent portion of the inner peripheral wall 23 is stretched during blow molding is reduced, and the plate thickness of the bent portion of the inner peripheral wall 23 is suppressed from being thinned.

(3) The inner peripheral wall side concave portion 41 is composed of a bottom portion 43 and side portions 45 obliquely extending from the peripheral edge of the bottom portion 43 toward the inner peripheral side while increasing in diameter.

A side surface portion 45 forming the inner peripheral wall recessed portion 41 obliquely extends from the peripheral edge of the bottom portion 43 toward the inner peripheral side while increasing in diameter. Therefore, compared to the case of extending from the peripheral edge of the bottom portion 43 to the inner peripheral side without expanding the diameter, the elongation rate at which the bent portion of the inner peripheral wall 23 is stretched during blow molding is further reduced, and the bent portion of the inner peripheral wall 23 is stretched. Thinning of the plate thickness is further suppressed.

The present invention is not limited to the above-described embodiments, and various modifications and variations are possible based on the technical idea of the present invention.

For example, the blow-molded article is not limited to having a thickness direction center CL1 that draws a single arc as shown in FIG. The center of the thickness direction is an arc drawn with a radius of , and the lower side of the blow molded body is smaller than the one dimension and is smoothly continuous with the center of the upper thickness direction. Alternatively, only the coupling portion 47 and its vicinity may be formed in an arc shape having a center CL1 in the thickness direction, and the other portions may be integrally continuous as a flat plate-like hollow body to form a substantially V shape when viewed from the side. can be

In addition, although the load absorbing member 9 arranged in the lid 3 of the glove box 1 has been described as an example of the blow-molded article, the present invention is not limited to this and can be applied to various blow-molded articles. .

9 Load absorbing member (blow molded body)
21 outer peripheral wall 23 inner peripheral wall 33 outer peripheral wall side recess 35 bottom (partial)
41 inner peripheral wall side recess 43 bottom (partial)
45 Side portion 47 Joint portion 49 Hollow portion

Claims (2)

At least a portion thereof is curved in an arc when viewed from the side, and in a cross section along the arcuately curved circumferential direction, the outer peripheral wall is arranged on the outer peripheral side and is spaced from the outer peripheral wall to the inner peripheral side in the thickness direction. A flat blow-molded body in which a hollow portion is formed between the inner peripheral wall arranged as
The outer peripheral wall and the inner peripheral wall are partly joined via a joining portion,
The connecting portion is arranged on the outer peripheral side of the center in the thickness direction of the outer peripheral wall and the inner peripheral wall facing the outer peripheral wall,
A portion of the outer peripheral wall that curves in an arc when viewed from the side is formed with an outer peripheral wall side concave portion that is recessed toward the inner peripheral side in the vicinity of the coupling portion, and the inner peripheral wall curves in an arc when viewed from the side. Inner peripheral wall side recesses that are recessed toward the outer peripheral side are formed in the parts in the vicinity of the joints, and the bottoms of the outer peripheral wall side recesses and the bottoms of the inner peripheral wall side recesses are joined to form the joints. and
A blow-molded article, wherein the maximum value of the length of the inner peripheral wall side along the circumferential direction of the inner peripheral wall side recess is larger than the maximum value of the outer peripheral wall side length of the outer peripheral wall side recess along the circumferential direction. . The blow molded article according to claim 1,
A blow-molded article, wherein the recess on the side of the inner peripheral wall is composed of the bottom portion and side portions extending obliquely from the peripheral edge of the bottom portion toward the inner peripheral side while increasing in diameter.

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