JPH06254915A - Speaker grille monolithic molding method - Google Patents

Abstract

PURPOSE:To prevent the exposure of weld and reduce the assembly man-hours by providing a first gate for an open collecting section forming mold and a second gate for a conventional section forming mold, forming a weir section for narrowing the interval of cavities on the boundary of both mold faces, controlling the injection timing of both gates and positioning a weld section on the weir section. CONSTITUTION:First, molten resin is injected out of a first gate 22, and molten resin injected out of a second gate 23 just a little later is flowed in a caivty for a conventional section 12 until flowing close to a cavity for an open collecting section 11. As a narrow cavity 32 is formed by a weir section 26 on the boundary of both resins, the cavity for the conventional section 12 is filled first. On the other hand, molten resin from the first gate 22 is interrupted similarly by the weir section 26 and filled in the cavity for the open collecting section 11 first, and then starts to flow into the cavity for the conventional section 12 where the resin from the second gate 23 has been filled prior to the delayed timing of injection of the resin from the first gate, and both resins are fusion melted together in the first narrow cavity 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a door trim of an automobile, a package G / N, or the like, and a set of a plurality of small-diameter through-holes for mounting a speaker on the back surface and leading a sound from the speaker to the front side. The present invention relates to a method for integrally molding a speaker grill having a portion.

[0002]

2. Description of the Related Art It is necessary to provide a speaker for a car radio or a car audio device in a vehicle interior, and the speaker is generally provided on the back side of a panel such as a door trim or a package G / N. In order to guide the sound emitted from the speaker into the passenger compartment, the panel is partially provided with an opening collecting portion in which a plurality of small-diameter through holes for leading out are collected.

By the way, when an attempt is made to integrally mold a panel having such a general portion and an opening collecting portion from a resin, a plurality of pins for forming a through hole are projected on the mold surface forming the opening collecting portion, At that part, the surface area of the mold surface becomes extremely large. Therefore, the molten resin has a large degree of cooling at that portion, and the fluidity is partially deteriorated, and there is a problem that the weld line appears as uneven gloss and the appearance is impaired. On the other hand, when the injection pressure is increased to improve the fluidity, burrs are more likely to be generated from the mold splitting surface, resulting in a large number of post-processing steps.

Therefore, conventionally, a separately formed metal punching metal or resin opening assembly is assembled into a resin panel formed as a general part to integrally form a speaker grill.

[0005]

However, in the method of separately forming the opening collecting portion and the general portion and assembling and integrating them, the number of assembling steps is great and the positions of the two members are displaced. In some cases, a defective product may occur. In addition, when assembling a metal punching metal, the punching metal itself is expensive, so that the total cost is increased.

The present invention has been made in view of the above circumstances, and the opening gathering portion and the general portion are integrally formed from resin, the weld is prevented from being exposed, and the burr from the mold splitting surface is prevented. The purpose is also to prevent the occurrence of.

[0007]

The speaker grill integral molding method of the present invention for solving the above-mentioned problems is a method for integrally molding a speaker grill having an opening gathering portion in which a plurality of small-diameter through holes are gathered from a resin. A first gate opening on the mold surface forming the opening collecting portion and a second gate opening on the mold surface forming the general portion other than the opening collecting portion, and forming the opening collecting portion and the general portion, respectively. A molding die having a weir portion that narrows the space between the cavities is used at the boundary portion of the mold surface, and the injection timing of the molten resin from the first gate and the second gate is controlled to position the weld portion on the weir portion. It is characterized in that it is molded as described above.

[0008]

In the speaker grill integral molding method of the present invention, the molten resin is injected from the first gate opening on the mold surface forming the opening collecting portion and the second gate opening on the mold surface forming the general portion. Then, the injection timing of each gate is controlled so that the resin injected from the first gate and the resin injected from the second gate are fused at the dam portion.

Here, in the dam portion, the space between the cavities is narrowed and the flow resistance is large, so that the resin flowing from both sides is temporarily blocked by the dam portion.
Therefore, it is easy to control the injection timing so that the weirs are fused. In the obtained speaker grill, the groove portion formed by the weir portion borders the periphery of the opening collecting portion, and the groove portion can function as one design. Further, since the weld line is located inside the groove, it does not stand out and does not spoil the appearance even if it appears as uneven gloss.

[0010]

EXAMPLES The present invention will be specifically described below with reference to examples. In this embodiment, the present invention is applied to the manufacture of the door trim lower shown in FIGS. 3 and 4. This door trim lower 1
Is a circular opening collecting portion 11 in which a plurality of small-diameter through holes 10 are collected and a speaker is attached to the back surface, and an opening collecting portion 1
1 and a general portion 12 around the circumference 1. A ring-shaped groove 13 is formed on the front surface side of the boundary between the opening collecting portion 11 and the general portion 12, and a rib 14 protruding cylindrically is formed on the rear surface side. The groove 13 functions as a design, and the rib 14 has a function of preventing sound emitted from the attached speaker from leaking to the side.

1 and 2 show a molding die used in this embodiment. This molding die is composed of a fixed die body 2 and a movable die body 3, and the fixed die body 2 is provided with two hot runner nozzles 20 and 21 having valve gates. A control mechanism (not shown) is connected to each of the hot runner nozzles 20 and 21, and the opening / closing timing of the valve gate can be freely adjusted.

The hot runner nozzle 21 has a general section 12
Second gate 23 opened at the end of the cavity forming the
The hot runner nozzle 20 is connected to
It is connected to the first gate 22 that opens into the cavity forming 1. The fixed mold insert 24 and the movable mold insert 30 are detachably fixed to a portion forming the opening collecting portion 11. The fixed insert 24 and the movable insert 30
As shown in an enlarged view in FIG. 2, pins 25 and 31 projecting toward the inside of the cavity are formed on the mold surface, and the through holes 10 are formed by abutting the opposing pins 25 and 31. Is configured. And pin 2
The first gate 22 is provided at a position away from the second gate 23 with respect to the center of the opening collecting portion 11 between the five.

At the boundary between the fixed mold insert 24 and the fixed mold main body 2, a weir portion 26 protruding toward the cavity is formed, and a space is narrowed between the weir portion 26 and the movable mold nest 30. A narrow cavity 32 is formed. The weir portion 26 is provided in a ring shape on the entire circumference of the fixed mold nest 24, and the narrow cavity 32 is also formed in a ring shape along the weir portion 26. A cylindrical cavity 33 for forming the rib 14 is formed between the movable mold insert 30 and the movable mold body 3.

A door trim lower was formed in the following manner using the molding die having the above structure. First, the valve gate of the hot runner nozzle 20 is opened while the valve gate of the hot runner nozzle 21 is closed, and the molten resin is injected from the first gate 22. Then, after a slight delay, the valve gate of the hot runner nozzle 21 is opened, and the same molten resin is injected from the second gate 23.

The molten resin injected from the second gate 23 flows through the cavity forming the general portion 12 and approaches the cavity forming the opening collecting portion 11. However, since the narrow cavity 32 exists at the boundary between the two due to the weir portion 26, the flow resistance rapidly increases at that portion.
Therefore, the molten resin flows into the cavity having a small flow resistance. That is, the cavity that flows along the dam portion 26 to form the general portion 12 is first filled while being assisted by the presence of the cylindrical cavity 33.

On the other hand, the molten resin injected from the first gate 22 is dammed by the dam 26 in the same manner as the general part 1.
It is prevented from flowing into the cavity forming 2 and the cavity forming the opening collecting portion 11 is first filled. Then, after the cavity forming the opening collecting portion 11 is filled, it tries to flow into the cavity forming the general portion 12 through the narrow cavity 32, but due to the effect that the injection timing is delayed, it is just 2 gate 2
The resin injected from 3 fills the cavity forming the general portion 12.

Therefore, the resin injected from the first gate 22 and the resin injected from the second gate 23 are fused at the narrow cavity 32. Then, after the molten resin is solidified, the movable mold 3 is opened and the ejection pin 34 is driven to release the molded body. That is, in the obtained molded body, the weld line is formed inside the groove 13 along the groove 13 in a ring shape. Therefore, even if uneven gloss due to welds occurs, since it is inside the groove 13, it is hardly observed from the outside and the appearance is not impaired.

[0018]

According to the speaker grill integral molding method of the present invention, it is possible to integrally mold the opening collecting portion and the general portion while avoiding the appearance defect due to the weld line. Therefore, the punching metal and the like which have been used conventionally are not required, and the number of assembling steps and the number of parts can be reduced. This makes it possible to reduce costs.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating the configuration of a molding die used in an example of the present invention.

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

FIG. 3 is a plan view of a door trim lower as a molded body formed in one embodiment of the present invention.

FIG. 4 shows a molded body formed according to one embodiment of the present invention,
FIG. 4 is a sectional view taken along line AA of FIG. 3.

[Explanation of symbols]

1: Door trim lower 2: Fixed type
3: Movable type 10: Through hole 11: Opening collecting part
12: General part 13: Groove 14: Rib
22: First gate 23: Second gate 26: Weir
32: Narrow cavity

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akiyoshi Nagano 1 Ochiai, Kasuga-cho, Nishikasugai-gun, Aichi Prefecture Nagahata No. 1 within Toyoda Gosei Co., Ltd. Nagahata No. 1 Toyota Toyoda Gosei Co., Ltd. (72) Inventor Hiroshi Suyama Azai Prefecture Kasuga-cho, Kasuga-cho Ochiai, Nagahata No. 1 Toyoda Gosei Co., Ltd.

Claims (1)

[Claims] 1. A method of integrally molding a speaker grill having an opening collecting portion in which a plurality of small-diameter through holes are collected, from a resin, the first gate opening to a mold surface forming the opening collecting portion, A weir part having a second gate opening on a mold surface forming a general part other than the opening collecting part, and narrowing a space between cavities at a boundary part of each mold surface forming the opening collecting part and the general part. A speaker grill, characterized in that a molding die having the above is used to control the injection timing of the molten resin from the first gate and the second gate so that the weld portion is located at the weir portion. One-piece molding method.