JPH0218020A - Insert-molded item and fixing method of insert member in mold - Google Patents

Abstract

PURPOSE:To prevent the deformation of a molded item due to the shrinkage of resin from occurring and facilitate the fixation of an insert member to a mold by method wherein the tip of the insert member is slidably inserted in the inserting hole of an insert fixing member under the condition that a certain gap is provided between the rear end wall of the inserting hole and the tip face of the insert member. CONSTITUTION:The tip part of an insert member 3 is inserted in the inserting hole 26 of an insert fixing member 2 under the condition that a gap 5 is provided between the rear end wall 27 of the inserting hole 26 and the tip face of the insert member 3. Next, a positioning pin 35, which protrudes in the cavity 34 of a movable mold 33 constituting one half of an injection mold, is fitted to a pin hole 25, which is provided on the under surface of the insert fixing member 2, so as to install the insert member 3 in the cavity 34. In this case, the insert fixing member 2 is fixed near the central part of the cavity 34 so as not to disturb the flow of molten resin and functions as the holder of the insert member 3. Next, when the movable mold 33 is shifted in order to clamp the mold together with a fixed mold 36, a positioning pin 37, which protrudes from the fixed mold 36, is fitted to a pin hole 24, resulting in surely fixing the insert fixing member 2 into the cavity 34.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an insert molded product that includes an insert member as a reinforcing material among plastic molded products, and a method for fixing the insert member in a mold for injection molding.

(Prior art) In order to absorb large concentrated loads applied to plastic molded products or to facilitate the assembly of molded products,
It may be manufactured as a so-called insert molded product that includes an insert member.

For example, plastic pallets used for storing and transporting cargo are widely used because they have superior corrosion resistance and stain resistance compared to wooden pallets and metal pallets. However, plastic pallets not only have a large degree of deflection when loaded, but also have a large creep property, so that depending on their structure, if used for a long period of time, they will deform into a curved shape and become unusable. In order to prevent such deflection, so-called insert molding is performed in which a metal reinforcing material is built-in.

FIG. 5 is a perspective view showing an example of a plastic pallet with a portion cut away.

The plastic pallet 41 has supports 42 at the four corners and in the middle.
．． 43, with a metal reinforcing member 4 as an insert member in the upper deck board 44.
5 is built-in.

Moreover, FIG. 6 is a perspective view of a plastic chair,
A metal reinforcing member 47 is built inside the chair 46 as an insert member.

In order to create a structure containing these insert members, the insert member is set in advance in the movable mold of the injection mold, and while moving relative to the movable mold, the mold is clamped against one of the fixed molds and fixed. It is molded by injecting molten resin into the mold.

(Problems to be Solved by the Invention) First, in the conventional insert molding method, it is difficult to incorporate an insert member into a desired position of a plastic structure.

In other words, in order to directly fix the insert member in the mold, the insert member or the mold must be processed, which complicates the mold structure, and when the molten resin is injected into the mold, the insert is Components may shift from their predetermined positions.

Furthermore, in insert molded product 1, the expansion and contraction of the insert member and the resin are different, and the resin is much larger, so the molded product is deformed by the contraction of the resin.
Alternatively, internal strain often occurs on the outer periphery of the insert member, causing cracks. Expansion and contraction of the resin are constantly repeated even after molding, and stress cracks also occur due to these repetitions.

Further, since the insert member holding portion of the mold is not filled with resin, there is a problem in that the portion must be filled after the product is molded.

This invention was made in view of the above points, and it prevents deformation of the molded product due to resin contraction, makes it easy to fix the insert member to the mold, and ensures that the insert member is in the desired position without shifting due to resin pressure. The object of the present invention is to provide a method for fixing an insert member that can be built into a device.

(Means for solving problems) In order to achieve the above purpose, the following configuration was adopted.

That is, in the insert molded product of the present invention, the insert fixing member attached to the molded product main body has a positioning portion in two directions for fixing to the mold, and an insert member insertion hole that intersects with the positioning portion, A predetermined gap is provided between the rear end wall and the tip end surface of the insert member in the hole, and the tip end of the insert member is slidably inserted, so that all or part of the positioning portion is exposed or buried. It is something.

Then, as a method for fixing the insert member in the mold, first, a certain gap is formed in the insert member insertion hole formed in the insert fixing member between the front end surface of the insert member and the rear end wall of the insertion hole. The distal end of the insert member is slidably inserted into the cavity, and then the insert member is placed in the cavity by inserting the positioning part of the insert fixing member and the positioning part of the mold, and then the movable mold There is a fixing method in which the insert member is clamped with the fixed mold and the insert member is fixed via the insert fixing member.

(Function) The gap at the tip of the insert member acts as a clearance that absorbs the shrinkage of the resin, and the shrinkage of the resin does not cause deformation of the insert member itself or, by extension, the molded product. In addition to securely fixing the insert member in the mold, the insert fixing member also includes anti-slip members,
It can function as a connecting member.

Moreover, the insert member is easily fixed in a predetermined position simply by fixing the insert fixing member in the cavity, and will not be displaced by resin pressure during injection molding.

(Example) Hereinafter, this invention will be explained in detail based on examples.

FIG. 1 is a sectional view of the main part of the insert molded product, and FIG. 2 is a sectional perspective view of the insert fixing member.

1 is a plastic molded product body, 2 is an insert fixing member, and 3 is an insert member.

As the resin for manufacturing the molded article body 1, a usual resin used in injection molding is used, such as polyolefin resin such as polyethylene or polypropylene, polystyrene resin, acrylonitrile-styrene resin, or the like.

The insert fixing member 2 has seven runs 2 at the top and bottom of the body 21.
2.23 is provided, and a bin hole 24.25 is formed into which a positioning bin for the mold is inserted, a movable bin is inserted into one bin hole, and a fixed bin is inserted into the other bin hole. Ru.

Furthermore, the bottle holes 24 and 25 are provided on the side surface of the body portion 21.
A horizontal insert member insertion hole 26 is formed so as to intersect with. Although the insertion hole 26 has a bottom and is formed from only one direction, it may be formed so as to intersect from two or three directions.

The insert fixing member 2 not only fixes the insert member 3 in the mold, but also functions as a connection when assembling with other molded products. It is set up. Therefore, when the insert fixing member 2 is to function as a connection, it is desirable to use a resin or metal that is harder than the molded product body 1.

Since the insert member 3 is built-in as a reinforcing member, metal is usually used, but it may also be made of aluminum, rigid plastic, etc., and the cross-sectional shape may be round, square, or
Any type can be used depending on the shape and strength of the molded product, such as an H-shape or a hollow body. The insertion hole 26 is formed according to the cross-sectional shape of the insert member 3.

The distal end of the insert member 3 is slidably inserted into the portrait insertion hole 26, and there is a contraction of A void 5 is provided as a clearance for absorbing.

! @3 Figure is a cross-sectional perspective view showing another embodiment.

The insert fixing member 2a has a connecting hole 28 on the front end surface of the circular body 21a for connecting with other molded products, a conical shape on the rear end surface to improve resin flow, and an insert member insertion hole 26a. It is formed. Furthermore, the body 2
On the side surface of 1a, fixed parts 29. are arranged 180 degrees apart in the opposite direction.
30 are provided protrudingly, the fixing part 29 has a bottle hole 24a, and the fixing part 30 has a bottle hole 25a! 11! being played a role.

Although the tip end surface of the insert fixing member 2a having the connection hole 28 is exposed, the fixing portions 29 and 30 are embedded in the molded product main body la by the embedding material 32.

In this embodiment as well, a gap 5 is provided at the distal end surface of the insert member 3 inserted into the insertion hole 26a as a clearance for absorbing shrinkage of the resin.

Next, the method of fixing the insert member 3 using the insert fixing member 2 will be explained based on FIG. The insert member 3 is inserted so as to provide a gap 5 between the end wall 27 and the front end surface of the insert member 3, and the insert fixing member 2 is attached to the front end of the insert member 3. Next, a positioning bin 35 is installed to protrude into the cavity 34 of the movable mold 33 constituting the injection mold.
The insert member 3 is installed in the cavity 34 by fitting into the pin hole 25 provided on the lower surface of the insert fixing member 2.

At this time, the insert fixing member 2 is fixed approximately at the center of the cavity 34 so as not to obstruct the flow of the molten resin, and functions as a holder for the insert member 3.

Next, when the movable mold 33 is moved and clamped together with the fixed mold 36, the positioning pin 37 protruding from the fixed mold 36 fits into the pin hole 24 on the upper surface of the insert fixing member 2, and the insert fixing member 2 is inserted into the cavity. 34. That is, since the insert member 3 is reliably held by the insert fixing member 2, it will not shift due to resin pressure even during injection molding.

Therefore, if the cavity 34 is filled with molten resin after mold clamping, the insert member 3 is held by the insert fixing member 2 having the above-mentioned structure, and can be easily and reliably inserted into the mold without complicating the mold structure. be done.

It should be noted that the shape of the insert fixing member is not limited to the above-mentioned embodiment, and it is also possible to completely embed the entire insert. In addition, to fix the insert fixing member to the mold, the bottle of the mold was inserted into the bottle hole, but instead, the protrusions formed on the upper and lower surfaces of the insert member were inserted into the hole provided in the mold. Good too. Like this, the bottle hole 24.25
The bins 35 and 37 are formed as positioning parts, and their shapes are not particularly limited.

In addition, the insert fixing member may be made of the same material as the molded product body, but if it is used not only as a holding part for the insert 1 member but also as a connection to other molded products, it is preferable that it is made of a hard material. In addition, when the molded product is a plastic pallet and is used as an anti-slip member, it is made of a rubber-like elastic body with a large coefficient of friction. The present invention can be applied to any molded product as long as it is a structure that includes an insert member.

(Effects of the Invention) Since the present invention is configured as described above, it has the following effects.

That is, since a gap is provided in the tip end surface of the insert member, shrinkage of the resin is absorbed by the gap and deforms the insert member, thereby preventing deformation and cracking of the molded product.

In addition, the insert fixing member may be buried within the molded product body, but it can also be partially exposed and connected to other molded products, and the connection may be installed at the same time as the insert member is built in. I can do it.

Furthermore, the insert member is not directly fixed in the mold, but is fixed via the insert fixing member, so it is easy to fix in the mold, and it is securely fixed so that it will not shift due to resin pressure. is possible.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the main part of the insert molded product, Figure 2 is a cross-sectional perspective view of the insert fixing member, Figure 3 is a cross-sectional view of the main part of another embodiment, and Figure 4 is a cross-sectional view of the insert molded product through the insert fixing member. FIGS. 5 and 6 are cross-sectional views of essential parts of a mold in which a member is fixed in a cavity, showing an example of a conventional insert molded product, FIG. 5 is a partially cutaway perspective view of a pallet, and FIG. The figure is a perspective view of the chair. Body 24.24a, 25.25a are bottle insertion holes 27
is the rear end wall of the insertion hole Patent applicant: Meiji Rubber & Chemicals Co., Ltd.

Claims (1)

[Claims] 1. The insert fixing member attached to the molded product body has a two-way positioning part for fixing to the mold, and an insert member insertion hole that intersects with the positioning part. A certain gap is provided between the end wall and the tip surface of the insert member, and the tip of the insert member is slidably inserted,
An insert molded product characterized in that all or part of the positioning portion is exposed or buried. 2. Slideably insert the insert member into the insert member insertion hole formed in the insert fixing member with a certain gap provided between the front end surface of the insert member and the rear end wall of the insertion hole, and then After arranging the insert member in the cavity by inserting the positioning part of the insert fixing member and the positioning part of the mold, the movable mold and the fixed mold are clamped, and the insert fixing member is inserted into the mold. A method for fixing an insert member in a mold, the method comprising: fixing the insert member in a mold.