JPS6063134A - Insert molding for fiber-reinforced plastic structural body - Google Patents

Abstract

PURPOSE:To improve the jointing strength by a method wherein a fiber train of a sheet-shaped base material yet not to be hardened is bent to make a hole and after an insert is put thereinto and then, the fiber train folded is undone to be hardened with a resin. CONSTITUTION:A pointed bar is put into the insert mounting position and bent a fiber train 1 to make an insertion hole 3. An insert 4 provided with an insert clamping section 6 is inserted into the hole and the fiber train is pulled so that the fibers positioned at the innermost point of the insertion hole 3 may be adjacent to a cylinder section 7, ultimately back to the original position. Then, an epoxy resin is injected thereinto to be hardened by heat.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for insert molding into a fiber-reinforced plastic structure in which protrusions such as metal fittings and inserts are scattered or formed in the fiber-reinforced plastic structure. .

(Prior Art) As methods for attaching protrusions to a fiber-reinforced plastic ink structure, there are a method of adhering the protrusions after molding the structure, a method of molding the protrusions simultaneously with the molding of the structure, and the like. Compared to the casting method, the bonding method requires more bonding steps, and bonding strength is low if only plane bonding is used, so a structure is required in which the bonding surface M is as wide as possible. In many cases, the surface measurement part of the pilot hole increases the bonding area, and in order to make it possible to apply shear force in the detachment direction, the pilot hole is inserted into the structure at the base of the protrusion. A method is adopted in which the In this case, it is necessary to prepare a pilot hole, and the fibers of the structure are cut during processing, which is one of the causes of a decrease in the strength of the entire product and the joint. On the other hand, in the case of the casting method, it is not possible to use fluid materials such as sheet molding compound (BMC) and Takhalk molding compound (BMC), which results in low joint strength and poor product quality. Overall, strength and rigidity were limited due to the necessity of using sheet molding compound or T4T rec molding compound.

(Object of the Invention) The present invention is intended to improve the above-mentioned drawbacks, and provides a method for insert molding into a fiber-reinforced plastic structure, which can reduce the number of bonding steps and improve the bonding strength.

(Structure of the Invention) The present invention is characterized by a step of forming holes by bending fiber rows at predetermined positions in a sheet-like base material made of continuous fibers before resin hardening, and forming holes in the holes substantially parallel to the sheet-like base material. This method consists of a step of inserting an insert fastening section provided with a widening section, a step of returning the bent fiber rows of the sheet-like base material to the original position, and a step of curing the resin.

(Function) With the above configuration, the present invention can insert and fix the insert into the structure without cutting the reinforcing fibers,
It becomes possible to prevent a decrease in the strength of the fiber-reinforced plastic structure at the base of the insert, and to increase the insert mounting strength.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

First, as shown in Fig. 1, as a fiber-reinforced plastic structure, a sheet-like base material 2 made by laminating plain-woven cloth of carbon fibers 1 to a predetermined thickness is prepared, and a tapered tip with an acute angle is prepared at the insert mounting position. Insert the rod (not shown) and
The fiber row is bent to form an insert insertion hole 5.

As shown in FIG. 2, the insert 4 has a cylindrical main body 5 and an insert fastening portion 6 provided at the bottom thereof. The insert fastening part 6 includes a cylindrical part 7 having a diameter smaller than that of the main body 5, and a disc-shaped ring 8 having a larger diameter than the cylindrical part 7 at the lowest part of the cylindrical part 7. A surface parallel to the axis is formed, and an end surface 9 connected to the cylindrical portion 7 of the main body 5 and an end surface 10 connected to the cylindrical portion 7 of the collar 8 are formed substantially parallel to the surface of the sheet-like base material 2. The height of the cylindrical portion 7 is made equal to the thickness of the sheet-like base material 2.

The insert insertion hole 3 formed in the sheet-like base material 2 is made larger than the diameter of the main body 5 or the collar 8 of the insert 4, whichever is smaller.

As shown in FIG. 3, insert the insert fastening part 6 into the insert insertion hole 3, and align the fiber rows so that the carbon fiber 1 located at the innermost side of the insert insertion hole 3 contacts the cylindrical part 7 of the insert fastening part 6. By pulling in the direction of the fibers, the bent fiber rows are returned to their original positions.

After the sheet-like base material 2 has been assembled with the insert, it is placed in a mold, and an epoxy resin is injected into it and then heated and cured to form a fiber-reinforced plastic structure with an insert.

As an example of application of such a method, as shown in FIG. 4, a prismatic cylindrical braid 12 made of continuous fibers 11 with prismatic inserts 16 attached between the fibers can be produced.

In this way, in the above embodiment, the insert 4 or 13 can be inserted and fixed without cutting the carbon fiber 1 or the general continuous fiber 11 in the middle, and then the plastic material is heated and hardened, so that the insert alone can be fixed. The adhesion process can be omitted. Moreover, the reinforcing fibers 1.11 around the insert mounting portion of the structure are denser than in other parts, making it possible to increase the strength of the insert mounting portion. This method can be applied regardless of the overall shape of the fiber-reinforced plastic structure as long as the reinforcing fibers in the insert attachment portion form a sheet.

(Effects of the Invention) As described above, the present invention bends fiber rows to form holes in predetermined positions of a sheet-like base material, inserts the fastening portion of the insert into the holes, and then inserts the bent fiber rows back into the original position. By returning the reinforcing fibers to this position, the insert can be inserted and fixed into the fiber-reinforced plastic structure without cutting the reinforcing fibers.

Therefore, it is possible to prevent a decrease in the strength of the fiber-reinforced plastic structure at the base of the insert, and to increase the strength for attaching the insert. Furthermore, unlike when inserts are glued after the plastic is cured and molded,
Because the inserts are assembled before curing, the plastic curing process simultaneously fixes the inserts, eliminating the need for individual bonding processes for the inserts.

[Brief explanation of the drawing]

FIG. 1 is a perspective explanatory view showing a state in which holes are formed by bending fiber rows in a sheet-like base material according to the present invention, FIG. 2 is a perspective view of a cylindrical insert according to the present invention, and FIG. 3 is a diagram similar to that shown in FIG. FIG. 4 is a perspective partial cross-sectional explanatory view showing a state in which an insert is inserted in a cross section taken along the line ■-■ of FIG. 4. FIG. DESCRIPTION OF SYMBOLS 1... Carbon fiber, 2... Sheet-like base material, 6... Insert insertion hole, 4... Insert, 5... Insert main body, 6... Insert fastening part, 7... Cylindrical Part 8...Brim? , 1o... End face patent applicant Toyota Motor Corporation

Claims (1)

[Claims] (1) A step of forming holes by bending fiber rows at predetermined positions in a sheet-like base material made of continuous fibers before resin hardening;
a step of inserting an insert fastening section provided with an expanded portion substantially parallel to the sheet-like base material into the hole; a step of returning the bent fiber rows of the four sheet-like base materials to their original positions; and a step of curing the resin. A method for insert molding into a fiber-reinforced plastic structure, comprising the steps of: