JP3218751B2 - Insert molding method in FRP - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding method for integrally molding an insert such as a stud bolt when molding an FRP product by RTM or the like.

[0002]

2. Description of the Related Art In recent years, FRP (glass fiber reinforced resin) products have been used for various molded products such as outer panels of automobiles. For example, when the engine hood is made of FRP, a plurality of reinforcing fibers such as glass fibers are laminated and molded in a mat shape in advance to secure the rigidity and strength of the molded product.
This glass fiber mat is set in a mold and resin transfer molding (hereinafter, referred to as resin transfer molding) is performed by injecting molten resin into the mold.
RTM) is employed. In the case of molding an FRP engine hood, it is necessary to integrally mold a stud bolt for fixing a hinge for attachment to a body. As shown in FIG. 4, the stud bolt used is one in which a seat plate 14 is fitted to a stud bolt 13, and the stud bolt is integrally formed into an FRP product by RTM in the following manner. .

As shown in FIG. 5, a mold used for RTM includes a core mold 11 for molding the back surface of a product and a mold mold 12 for molding the outer surface. Each mold usually uses an electroformed shell. To form the molding surface. The stud bolt 13 is formed by embedding the head of the bolt and the washer 14 before molding the reinforcing core material 10 with a foam such as urethane foam,
Glass fiber mats 15 and 16 are arranged on both sides of the core material 10 and set in a mold. The core material 11 has a core material 1
A recess for setting 0 is formed, a rubber cap 17 made of silicon rubber or the like is put on the thread portion of the bolt 13 embedded in the core material 10, and the cap 17 is pushed into the recess of the core mold 11 to remove the core material 10. It is set at a predetermined position in the cavity of the mold. In the case of a skin panel not using a core material, as shown in FIG. 6, the stud bolt 13 is inserted through the back glass fiber mat 15,
A rubber cap 17 made of silicon rubber or the like is put on the screw portion of the bolt 13, and the cap 17 is pushed into the concave portion of the core mold 11 and set in a predetermined portion of the cavity of the molding die. The mat 16 is set. In any case, when the mold is clamped and the cavity is filled with the molten resin, the stud bolts 13 are embedded in the FRP product and are integrally formed.

Japanese Utility Model Application Laid-Open No. 64-1933 discloses that in a glass fiber reinforced RIM molded product having a mounting clip, a clip seat plate has a reinforcing glass mat on the molded product surface side and a seat plate on the molded product mounting surface side. A glass fiber reinforced RIM molded product which is sandwiched by fixing glass mats and buried in the RIM resin together with the two glass fiber mats, and in which the buried portion of the seat plate fixing glass mat projects toward the mounting portion side, I have. Further, Japanese Utility Model Application Laid-Open No. 63-25524 describes an FRP fastener in which a mounting surface of a fiber reinforced resin material in which a head of a fastening member is embedded is made convex.

[0005]

In the conventional method of setting the core member 10 shown in FIG. 5, if the dimension of the preformed core member 10 is slightly shifted, the position of the stud bolt 13 is shifted. The material 10 cannot be set on the core mold 11. Further, in the case of the skin panel shown in FIG. 6, the thickness of the FRP product is regulated by the thickness of the head of the stud bolt 13 and the thickness of the washer 14, so that a thin panel cannot be formed. In either case, the product structure is such that the washer 14 is used to receive the mounting strength of the stud bolt 13, so that it is difficult to install the stud bolt 13 in a narrow place.

[0006] None of the publications disclosed in the above publications disclose a molding method, and have a product structure that receives the mounting strength of the insert, so that it is difficult to install the insert in a narrow place. Not only that, if a large force is applied to the inserted bolt or the like, there is a possibility that the bolt may peel off between the FRP layers and break. The present invention solves the above-mentioned problems, and by integrally molding a reinforcing boss at the base of the insert, increases the mounting strength of the insert and mounts the insert even on a thin panel or a narrow place. It is an object of the present invention to provide an insert molding method in FRP that enables it.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a convex portion for entanglement of reinforcing fibers is formed in an enlarged diameter buried portion of an insert, and reinforcing fibers are arranged around the enlarged diameter buried portion to form an insert. An insert assembly sandwiched by elastic caps to be fitted is formed, and a concave portion for fitting the elastic cap of the insert assembly into a molding die and a concave portion for accommodating the enlarged diameter embedded portion of the insert holding the reinforcing fiber are formed. This is an insert molding method in FRP in which the insert assembly is set in the mold and molten resin is injected.

[0008]

[Function] Since the insert assembly is pre-configured and attached to the concave part of the molding die, the insert can be positioned and set with high precision, and the molded product has a boss-like shape with the reinforcing fiber around the enlarged diameter embedded part. A protrusion is formed on the insert base,
The mounting strength of the insert increases.

[0009]

FIG. 2 shows a cross section of a part of a molding die.
The upper mold is the core mold 1 for molding the back surface of the FRP product, the lower mold is the mold mold 2 for molding the outer surface of the product, and the cavity 3 is formed by both molds. The core mold 1 is provided with a mounting portion 1a of the silicone rubber cap 7 and a boss forming portion 1b as concave portions. The depth D of the boss forming portion 1b is made substantially equal to the sum of the thickness of the head of the stud bolt 4 and the thickness of the back glass fiber mat 5, and the back glass fiber mat 5 having the width L and the front glass fiber mat at the peripheral portion. An annular concave portion serving as a margin for overlapping with 6 is formed. The back glass fiber mat 5 is formed in a circular shape as shown in FIG.
A hole 5a through which the threaded portion is inserted is formed, and the outer edge portion 5b is loosened with glass fiber to reduce the density. Stud bolt 4
A nail 4a is formed around the head as shown in FIG.

As shown in FIG. 1, a back glass fiber mat 5 is inserted into the threaded portion of the stud bolt 4, glass fiber is entangled with the nail 4a around the head, and a silicone rubber cap 7 is put thereon. The cap 7 is assembled in advance, and the cap 7 is pushed into the mounting portion 1a of the core mold 1 and set on the core mold 1. When the front glass fiber mat 6 is set in the mold 2 and the mold is clamped, the head 4a of the stud bolt 4 holding the rear glass fiber mat 5 is disposed on the boss forming portion 1b of the core mold 1, and the back glass fiber mat The outer peripheral edge portion 5b of the upper surface 5 overlaps the front glass fiber mat 6.

When the molten resin is injected into the cavity, the resin is filled around the back glass fiber mat 5 and the front glass fiber mat 6, and the stud bolts 4 are integrally embedded in the boss forming portion. At this time, in order to prevent the molten resin at the portion in contact with the silicon rubber cap 7 from being uncured due to the heat insulating action of the silicon rubber, it is preferable to use silicon rubber mixed with aluminum powder. Cap 7
Is not limited to silicone rubber, and other elastic materials can be used. The stud bolt 4 integrally embedded in the boss forming part of the molded product has the back glass fiber mat 5 entangled at the head thereof, and the outer peripheral edge 5b of the back glass fiber mat 5 overlaps the front glass fiber mat 6 with a margin L. The stud bolt 4 is buried with sufficient strength even when the thickness of the product is small because it is joined to the front glass fiber mat 6 with a width of.

FIG. 3B shows another shape of the stud bolt. The stud bolt 8 has a dish-shaped head, a tooth 8a provided on an inclined surface thereof, and a glass fiber tangled with the tooth 8a when the back glass fiber mat 5 shown in FIG. 3A is inserted. It is. The threaded portion of the stud bolt 8 is covered with a silicone rubber cap 7 and
Is set in the core mold 1 by pushing it into the mounting portion 1a of the stud bolt 4 in FIG.

In the above embodiment, RTM molding was described. However, the present invention is also applicable to resin injection (RI) with a low injection resin pressure, and inserts can be applied not only to bolts but also to those having similar shapes. Since the mounting position is determined by the core-type mounting portion, high accuracy is achieved.

[0014]

According to the present invention, the work of mounting the insert is easy, the accuracy of the mounting position of the insert is high, the mounting strength is increased, and the insert can be mounted on a thin panel or a narrow place.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of one embodiment of the present invention.

FIG. 2 is a partial sectional view of a mold used in the present invention.

FIG. 3 is a partial cross-sectional view showing a state of being attached to a fiber mat and a bolt used in the present invention.

FIG. 4 is a front view of a conventional stud bolt.

FIG. 5 is a sectional view of a conventional molding method.

FIG. 6 is a cross-sectional view of another conventional molding method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Core type 2 Cabinet type 4,8 Stud bolt 5 Back glass fiber mat 6 Front glass fiber mat 7 Silicone rubber cap

Continued on the front page (51) Int.Cl. ⁷ Identification code FI B29C 45/36 B29C 45/36

Claims (1)

(57) [Claims] 1. A convex portion for entanglement of a reinforcing fiber is formed in an enlarged diameter buried portion of an insert, and a reinforcing fiber is disposed around the enlarged diameter buried portion and is sandwiched by an elastic cap fitted to the insert. Forming an insert assembly, a recess for fitting an elastic cap of the insert assembly in a molding die and a recess for accommodating an enlarged diameter buried portion of the insert holding reinforcing fibers, and forming the insert in the molding die; An insert molding method in FRP, wherein an assembly is set and molten resin is injected.