JP2013188984A - Synthetic resin molded product integrated with insert member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a molding resin from protruding to an end face of an insert member when embedding and integrating the insert member 2 having the end face E exposed to the outside of a molded product into the synthetic resin molded product 1.SOLUTION: An insert member 2 is arranged so that an end face E is positioned while protruding to the outside of a molded product rather than a general face S of the molded product in a portion into which the resin molded product is embedded, a resin hollow part 101 protruding from a general face S of the molded product in a hollow shape is integrally formed at the molded product 1 so as to surround the periphery of the end face portion of the insert member 2, and D/240≤t≤D/80 is satisfied with a representative dimension of the end face E of the insert member as D, and the thickness of the resin hollow part 101 as t. Furthermore, it is preferable that a protrusion amount H of the end face E protruding to the outside of the molded product from the general face S of the molded product may satisfy D/240≤H≤D/80.

Description

The present invention relates to a synthetic resin molded product formed by injection molding of a synthetic resin. In particular, the present invention relates to a synthetic resin molded product in which an insert member is embedded and integrated by insert molding.

Synthetic resin molded products formed by injection molding of synthetic resins are used in various applications in various forms such as cases, covers and caps. And these synthetic resin molded products may be provided with insert members such as nuts and collars in a part thereof. Such an insert member is embedded and integrated in a synthetic resin molded article using a so-called insert molding technique in which resin is injected in a state where the insert member is disposed inside the mold.

In particular, when the insert member is a member of a fastening portion such as a collar or a nut, the molded product is often formed such that the end surfaces (fastening surfaces) of these members are exposed to the outside of the molded product. In that case, if the molding resin protrudes from the end face of the insert member, it may cause insufficient fastening or a defect such as cracking of the molded product. Further, the protrusion of the resin to the end face may impair the appearance quality of the molded product. Therefore, when the end surface of the insert member is exposed outside the molded product, it is necessary to prevent the resin from protruding from the end surface portion.

In order to solve such problems, it is effective to make molds and insert members more precise and highly accurate, to increase the adhesion between the mold and the insert member end face, and to prevent leakage of molding resin. It is known. However, refinement of molds and insert members is naturally limited in terms of manufacturing costs.

For example, as shown in Patent Document 1, a technique is known in which the shape of the end surface of the insert member is devised so that the molded resin does not leak.
Further, for example, as shown in Patent Document 2, a fixing means for fixing an insert member to a mold is provided, and the fixing means is devised so that a gap between the mold and the insert member is eliminated. A technique for preventing leakage is known.

JP 2004-42561 A Japanese Patent Laid-Open No. 06-063987

An object of the present invention is to prevent the synthetic resin from protruding to the end face of the insert member by other technical means.

As a result of intensive studies, the inventor made the end surface portion of the insert member to be exposed protrude from the resin molded body, and provided a thin resin hollow cylindrical portion so as to surround the periphery of the end surface. As a result, it was found that it was possible to prevent the protrusion of the above, and the present invention was completed.

The present invention is a synthetic resin molded product formed by injection molding of synthetic resin, and in the molded product, an insert member having an end surface exposed to the outside of the molded product is embedded and integrated by insert molding, The molded product is such that the end surface is located at a position protruding outward from the molded product general surface of the portion where the insert member is embedded in the resin molded product, and surrounds the periphery of the end surface portion of the insert member. A hollow resin cylindrical portion protruding in a hollow cylindrical shape from a general surface is integrally formed in the molded product, where D is the representative dimension of the end surface of the insert member and t is the thickness of the hollow resin cylindrical portion, and D / 240 ≦ t ≦ D. / 80 is a synthetic resin molded product (first invention).

In the first aspect of the invention, it is preferable that D / 240 ≦ H ≦ D / 80, where H is the amount of protrusion that the end face protrudes outward of the molded product from the general surface of the molded product (second invention).
In the first and second inventions, the insert member is preferably provided with two end faces exposed to the outside of the molded product so as to face each other (third invention).

According to the synthetic resin molded product of the present invention, an effect of preventing the synthetic resin from protruding to the end face of the insert member can be obtained.

Furthermore, if the protrusion amount H is determined as in the second invention, the protrusion of the synthetic resin to the end face can be more reliably prevented.

The front view, partial perspective view, and sectional drawing of the resin molded product of 1st Embodiment of this invention. The expanded sectional view which shows typically the cross section of the insert member vicinity in this invention 1st Embodiment. The schematic diagram which shows the process of forming the resin molded product of 1st Embodiment of this invention by insert molding. The figure which shows the cross section of the example of the insert member in this invention.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings, taking as an example a cap member in which a collar is embedded and integrated. The present invention is not limited to the individual embodiments shown below, and can be carried out by changing the form.

The synthetic resin molded product 1 according to this embodiment is a cap. The cap 1 is a member formed by injection molding of synthetic resin. The cap 1 is provided with two fastening portions, in which metal insert members (collars) 2 and 2 are embedded and integrated. That is, the insert member in this embodiment is a collar. FIG. 1 shows a front view and a sectional view of the cap 1 and a partial perspective view of the vicinity of the collar. The cap 1 can be fixed to another member by inserting a bolt through the collar portion and fastening the bolt.

Although resin which comprises the molded article main-body part 10 of the synthetic resin molded article 1 is not specifically limited, For example, injection-moldable thermoplastic resins, such as a polypropylene resin, can be used.

FIG. 2 schematically shows an enlarged cross-sectional view of the molded product 1 in the vicinity of the collar 2.
The collars (insert members) 2 and 2 embedded in the cap 1 are embedded and integrated in the cap 1 by so-called insert molding.

In the present invention, the insert member is a member that is formed in advance prior to injection molding for forming the synthetic resin molded product (cap 1) and is embedded and integrated into the resin molded product by insert molding. is there. The insert member may be made of metal or resin. Examples of the insert member include a collar and a nut.

In this embodiment, the insert member (collar 2) is a metal hollow cylindrical member, and has planar end faces E at both ends in the axial direction. In this embodiment, two end surfaces E and E are provided so as to face each other. Such a collar form is particularly preferable in the fastening structure. In the cap 1, the end faces E and E of the collar are exposed to the outside of the molded product (cap 1). And it is provided in the position where the end surface E of the collar protrudes outward of the molded product rather than the molded product general surface S of the part where the insert member (collar 2) is embedded in the molded product (cap 1). . That is, the collar 2 is embedded and integrated so that the end face portion protrudes from the cap body 10. In the present embodiment, the end face E of the collar protrudes from the cap body 10 at both end faces of the collar.

A hollow cylindrical resin hollow cylinder 101 is formed so as to protrude from the molded product general surface S of the cap body 10 along the outer peripheral surface of the insert member so as to surround the end surface portion of the insert member (collar 2). It is integrally formed with the molded product (cap 1). That is, the resin hollow cylinder portion 101 protrudes from the cap body 10, and the resin hollow cylinder portion 101 surrounds the collar 2 and is disposed so as to be in close contact with the outer peripheral surface of the collar 2. In the present embodiment, since the outer peripheral surface of the insert member is columnar, the resin hollow cylinder portion is a thin cylindrical shape. However, if the outer peripheral surface of the insert member is a prismatic shape, the resin hollow cylindrical portion is a thin rectangular tube shape. Is done.

The shape of the resin hollow cylinder portion 101 formed in a hollow cylinder shape around the insert member will be described in detail. The thickness t of the resin hollow cylinder portion 101 is determined based on the representative dimension D of the end surface of the insert member 2. Here, the thickness t of the resin hollow cylinder is a thickness dimension measured in a direction penetrating the resin hollow cylinder from the inside to the outside as shown in FIG. 2 (in this embodiment, the radial direction of the cylinder). ). Further, the representative dimension D of the end face of the insert member is a dimension indicating the size of the end face outer shape. If the end face is circular, its diameter is indicated. If the end face is oval, its major axis is indicated. If present, the length of the long side or diagonal line can be treated as the representative dimension of the end face, and if the end face is polygonal, the diameter of the circle that encompasses the end face can be handled. In the present embodiment, the representative dimension D of the end surface is the outer diameter dimension of the collar 2. The typical dimension D of the end face of the insert member is typically 5 to 50 mm in many cases. The representative dimension D is particularly preferably 7 to 30 mm in carrying out the present invention.

The thickness t of the resin hollow cylinder portion 101 is determined so as to fall within the range of D / 240 ≦ t ≦ D / 80 with reference to the representative dimension D of the end face of the insert member (collar 2). That is, the resin hollow cylinder portion 101 is provided considerably thin with respect to the size of the collar.

Further, it is preferable that the projection amount H projects from the molded product general surface S to the outside of the molded product H, and the projection amount H is also determined based on the representative dimension D of the end surface of the insert member 2. It is preferable to be determined so as to fall within the range of 240 ≦ H ≦ D / 80.

Further, as shown in FIG. 2, the protruding amount of the resin hollow cylindrical portion 101 is made smaller than the protruding amount H of the end surface E, and the gap between the end surface E of the collar 2 and the distal end portion of the resin hollow cylindrical portion 101 is reduced. It is particularly preferred that a gap G exists.

A method for producing the synthetic resin molded product (cap 1) will be described.
First, an insert member (collar 2) is manufactured in advance. The insert member can be produced by a known method.

Next, the synthetic resin molded product 1 is insert-molded using the insert member 2. FIG. 3 schematically shows the insert molding process in a cross-sectional view in the vicinity of the insert member 2.
The injection molds D1 and D2 used for insert molding are formed so as to be able to form a cavity that matches the outer shape of the synthetic resin molded product 1.

In the molds D1 and D2, the part with which the end face of the insert member (collar 2) abuts is formed in a spot facing shape. The diameter D 'and the depth of the spot facing are determined so that the thickness t of the resin hollow cylindrical portion and the protrusion amount H of the end face E can be obtained with respect to the outer shape D of the collar 2.

As shown in this embodiment, when both end faces E, E of the insert member (collar 2) are sandwiched between molds D1, D2, one end face E side can be biased by a spring or the like. It is preferable to use a movable holding structure. It is also a preferred embodiment that a pin P or the like is provided on the mold so that the insert member can be easily held and fixed.

An insert member (collar 2) is placed on the mold (FIG. 3 (a)), and the mold is closed.

With the mold closed (FIG. 3B), the resin is injected. Then, the molded product main body (cap main body 10) is formed while the resin hollow cylindrical portion (101) is formed in the space between the spot facing portion having the diameter D ′ and the insert member (collar 2) having the diameter D. .

Thereafter, after the resin is cooled and solidified, the molds D1 and D2 are opened, and the synthetic resin molded product (cap 1) in which the insert member (collar 2) is embedded and integrated is taken out (FIG. 3 (c)). .

The operation and effect of the present invention will be described.
In the present invention, the resin hollow cylinder part formed in a thin wall having a predetermined thickness so that the end surface E of the insert member (collar 2) protrudes from the molded product body 10 and surrounds the periphery of the end surface E. Since 101 is provided, it can prevent that resin protrudes into the end surface E of an insert member.

This is because, in the insert molding process, even if the injected resin tries to reach the end face E, a narrow space between the spot facing portion of the mold and the insert member (a space having a thickness t corresponding to the resin hollow cylinder portion 101). This is because the fluidity of the injected resin is lowered while passing through the portion, and it is difficult to enter the portion where the end face E and the mold come into contact.

Further, when a predetermined amount of protrusion H that the portion of the end surface E of the insert member (collar 2) protrudes from the molded product body 10 is secured, a gap G is formed between the tip of the resin hollow cylinder 101 and the end surface E. Can be formed. Then, the protrusion of the resin to the end surface E of the insert member can be more effectively prevented, and the end surface E of the insert member can be reliably protruded from the resin portion (molded product body). It is preferable when the end face is used for fastening.

Further, as shown in the present embodiment, when the insert member (collar 2) is provided with two end faces E and E exposed to the outside of the molded product so as to face each other, these end faces are formed by a mold. The insert member can be fixed so as to be sandwiched, and insert molding can be performed efficiently. That is, the production efficiency of the synthetic resin molded product can be increased.

The present invention is not limited to the above embodiment, and can be implemented with various modifications. Other embodiments of the present invention will be described below. However, in the following description, portions different from the above embodiment will be mainly described, and detailed descriptions of the same portions will be omitted. Further, the embodiments described below can be implemented by combining some of them or replacing some of them.

Although the case where the synthetic resin molded product is a cap has been described in the above embodiment, the molded product is not particularly limited. Examples of the molded product include a case member, a cover member, and a duct member.

The insert member embedded and integrated in the resin molded product is not particularly limited as long as it has an end surface exposed to the outer surface of the molded product. The material of the insert member is not particularly limited, such as metal or resin. The end surface E included in the insert member may be one surface, two surfaces opposed to each other as in the above embodiment, or three or more surfaces.

Although an insert member is not limited to the member used for a fastening part, this invention can be preferably utilized especially with respect to the insert member of a fastening part. In FIG. 3, the variation of the insert member which can be utilized for this invention is shown with a cross section. These insert members can be used in the present invention such that the respective end surfaces E are exposed to the outer surface of the molded product.

The insert member 21 is a hollow cylindrical collar member having end faces E on both sides. As in this embodiment, the insert member may be provided with a collar portion.
The insert member 22 is a hollow hexagonal nut member having end faces E on both sides. As in this embodiment, the insert member may be provided with a screw. Further, the outer peripheral shape of the insert member may be a prismatic shape as in the present embodiment. In that case, the resin hollow cylinder part of the resin molded product is also formed in a hollow rectangular tube shape.
The insert member 23 is a cap nut member with a collar having an end face E only on one side.

The insert member 24 is a boss member having end faces E on both sides. In this member, a shaft protrudes from each end face E. In addition, a plurality of ring-shaped uneven strips are formed on the side surface of the insert member 24 in order to strengthen the connection with the molded product body.
The insert member 25 is a stud member with a flange having an end face E only on one side. The stud portion protruding from the end surface E is provided with a screw.

A synthetic resin molded product according to the first embodiment of the present invention as shown in FIG. 1 was molded, and the effect of the present invention was confirmed. The synthetic resin constituting the molded product body 10 is a polypropylene resin. Color 2 is a steel color. Molding was performed when the color diameter was 10 mm.

In each case, the color and mold are modified to change the thickness t (t / D) of the resin hollow cylindrical portion 101 around the collar and the protruding amount H (H / D) of the collar end face, thereby forming the mold. Went. Table 1 shows the molding results when the collar diameter is 10 mm. In the values of t / D and H / D in Table 1, 0.0042 corresponds to 1/240, 0.0084 corresponds to 1/120, and 0.0125 corresponds to 1/80.

The evaluation of the molded product is based on whether the resin hollow cylinder part (cylindrical part) is formed around the collar, whether the molding resin protrudes from the collar end face, between the collar end face and the resin hollow cylinder part (cylindrical part) tip, Three points were evaluated whether a gap (gap G) was formed.

As in Comparative Example 1, when the thickness t of the resin hollow cylindrical portion is less than D / 240, the cylindrical portion is not formed. In this case, it is considerably difficult to attach the collar to the mold.

As in Example 1 to Example 3, when the thickness t of the resin hollow cylinder part is in the range of D / 240 ≦ t ≦ D / 80, the resin hollow cylinder part which is a feature of the present invention is formed. Further, the resin does not protrude from the end face of the collar. Further, a slight gap exists between the front end of the resin hollow cylinder and the end face of the collar, and the protrusion of the resin to the end face of the collar is reliably prevented.

As in Comparative Example 2 and Comparative Example 3, when the thickness t of the hollow resin tube portion exceeds D / 80, the resin protrudes from the end face of the collar. Even if the protrusion amount H of the color end face was increased to about D / 80, the protrusion of the resin to the color end face could not be stopped.

In Example 1 and Examples 4 to 7, an example in which the protruding amount H of the collar end face is changed with the thickness t of the oil hollow cylinder portion being D / 240 is shown. In any of the examples, the resin did not protrude from the end face of the collar. Further, when the protrusion amount H is in the range of D / 240 ≦ H ≦ D / 80 (Examples 1, 5, and 6), a gap is formed between the collar end surface and the tip of the resin hollow cylindrical portion, and the protrusion to the collar end surface is performed. The prevention of the resin from protruding is more reliable. Further, since there is a gap G, the molded resin does not protrude beyond the end face of the collar. In Example 4 in which the protrusion amount H was less than D / 240, the gap G was not formed. Moreover, even if the protrusion amount H exceeded D / 80 (Example 7), the gap G was not formed. That is, the gap G was formed when the protrusion amount H was in the range of D / 240 ≦ H ≦ D / 80.

In Example 3 and Examples 8 to 11, an example in which the protruding amount H of the collar end face is changed with the thickness t of the oil hollow cylinder portion being D / 80 is shown. In any of the examples, the resin did not protrude from the end face of the collar. Further, when the protrusion amount H is in the range of D / 240 ≦ H ≦ D / 80 (Examples 3, 9, and 10), a gap is formed between the collar end surface and the tip of the resin hollow cylinder, and the protrusion to the collar end surface is formed. The prevention of the resin from protruding is more reliable. Further, since there is a gap G, the molded resin does not protrude beyond the end face of the collar. In Example 8 in which the protrusion amount H was less than D / 240, the gap G was not formed. Moreover, even if the protrusion amount H exceeded D / 80 (Example 11), the gap G was not formed. That is, the gap G was formed when the protrusion amount H was in the range of D / 240 ≦ H ≦ D / 80.

Even when the diameter of the collar was 25 mm, the same molding confirmation was performed. Similarly, when the thickness t of the resin hollow cylinder portion is in the range of D / 240 ≦ t ≦ D / 80, the characteristics of the present invention are obtained. It was confirmed that a certain resin hollow cylinder portion was formed and the resin did not protrude from the end face of the collar.

INDUSTRIAL APPLICATION This invention can be utilized for the resin molded product which has an insert member, can prevent the protrusion of the resin to an insert member end surface, and its industrial utility value is high.

1 Synthetic resin molded product (cap)
2 Insert member (color)
E End surface 10 Molded product body 101 Resin hollow cylinder S Molded product general surface

Claims (3)

A synthetic resin molded product formed by injection molding of synthetic resin,
In the molded product, an insert member having an end surface exposed to the outside of the molded product is embedded and integrated by insert molding.
The end surface of the insert member is positioned at a position protruding from the molded product outside of the molded product general surface of the part embedded in the resin molded product,
The resin hollow cylinder part which protrudes in the shape of a hollow cylinder from the general surface of the molded product is integrally formed in the molded product so as to surround the end surface portion of the insert member,
The representative dimension of the end face of the insert member is D,
If the thickness of the resin hollow cylinder is t,
A synthetic resin molded product in which D / 240 ≦ t ≦ D / 80. The amount of protrusion by which the end surface protrudes outward from the molded product from the general molded product surface is H,
The synthetic resin molded product according to claim 1, wherein D / 240 ≦ H ≦ D / 80. The synthetic resin molded product according to claim 1 or 2, wherein the insert member is provided with two end surfaces exposed to the outside of the molded product so as to face each other.

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