JPS6120731A - Tubular molded body - Google Patents

Abstract

PURPOSE:To mold a void-free beautiful surface by extruding the resin in a prepreg to the surface thereof, by winding a prepreg sheet around a flexible tube and heating the whole in a mold before blowing compressed air into the flexible tube. CONSTITUTION:After a prepreg sheet 4 is wound around a rubber tube 5 through which a core 6 is inserted for the purpose of reinforcement, the core 6 is withdrawn from the rubber tube 5 to bring said tube 5 to an easily bendable flexible state. This rubber tube 5 having the prepreg sheet 4 wound therearound is held and set between molds 7, 8. After the completion of setting, preheating treatment is performed by a heater to bring the resin 3 of the prepreg sheet 4 to a flowable state. At this point of time, curing treatment is performed under heating while compressed air is blown into the rubber tube 5 projected from the molds 7, 8 from one end thereof. The resin 3 made flowable by preheating treatment moves to the outer surface of the cylindrical wound article to expel internal air and a molded article having a void free beautiful surface is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a tubular molded body formed from a prepreg sheet of reinforcing fibers.

[Prior art]

Conventionally, when forming a tubular body from a prepreg sheet, a prepreg sheet in which continuous filament reinforcing fibers are aligned in one direction is used, or a braided prepreg sheet in which the continuous filament reinforcing fibers are braided is used. is common.

However, when forming a unidirectional prepreg sheet or a braided prepreg sheet into a bent tubular body or a tubular body whose diameter changes in the length direction, the bending portion or the diameter changes. It is inevitable that the fiber density changes in some parts, and it is difficult to obtain high strength uniformity and isotropy over the entire molded body.

[Purpose of the invention]

An object of the present invention is to provide a tubular molded body that can provide high strength uniformity and isotropy over the entire molded body, even if the tubular body has a bent shape or changes in diameter in the longitudinal direction. It is about providing.

[Structure of the invention]

The tubular molded article of the present invention for achieving the above-mentioned object is a tubular body having a bent shape or having a diameter changed in the longitudinal direction, and the tubular body is a short tube impregnated with a thermosetting resin. It is characterized by being molded from a sheet-like material in which fibrous reinforcing fibers are randomly dispersed.

In the present invention, reinforcing fibers include carbon fibers, glass fibers,
High-strength, high-elastic fibers such as organic high-elastic fibers, silicon carbide fibers, alumina fibers, and boron fibers. These reinforcing fibers are canted into short fibers and dispersed in random directions.

Examples of the thermosetting resin impregnated into the reinforcing fibers include epoxy resin, unsaturated polyester resin, phenol resin,
Thermosetting resins such as polyimide resins are preferred.

[Embodiments of the invention]

Hereinafter, the present invention will be explained with reference to embodiments shown in the drawings.

FIG. 1 shows a bent tubular body used as a handle of a bat umbrella according to an embodiment of the present invention. The tubular body 1 having this bent shape is made by dispersing reinforcing fibers 2 in the form of short fibers such as carbon fibers in random directions, and integrally molding them together with a thermosetting resin 3 impregnated into the reinforcing fibers 2. ing.

The bent tubular body 1 can be manufactured, for example, by a molding method as illustrated in FIGS. 3 to 5.

FIG. 3 shows a prepreg sheet used as the material for the tubular body 1. This prepreg sheet 4 has a large number of reinforcing fibers 2 canted into short fibers, each of which is randomly dispersed in a sheet shape, and the reinforcing fibers 2 are made of a thermosetting material such as a semi-cured epoxy resin. It is impregnated with resin 3 to bond the reinforcing fibers 2 to each other.

As shown in FIG. 4, a rubber tube 5 is applied to the edge of the prepreg sheet 4 prepared as described above, and the prepreg sheet 4 is wound around the outer periphery of the rubber tube 5 in a cylindrical shape. The surface of the rubber tube 5 is coated with silicone in order to facilitate the operation when removing it from the molded product after being heated and cured.

When the prepreg sheet 4 is wound around the rubber tube 5, it is preferable that a core metal 6 is inserted into the center of the rubber tube 5 to provide sufficient rigidity. Moreover, it is preferable to apply a thermosetting resin such as a liquid epoxy resin to the surface to give it tackiness so that the prepreg sheet 4 can be easily attached.

By inserting the core metal 6 and applying the liquid resin in this way, the prepreg sheet 4 is rolled up into a cylindrical roll having a uniform and stable diameter. Prepreg sheet like this 4
Generally, the rubber tube 5 is wound in a single layer and then cut, but it may be wound in two or more layers if necessary.

After winding the prepreg sheet 4 as described above,
The core metal 6 is extracted from the rubber tube 5 and made into a flexible state that is easy to bend. Thereafter, as shown in FIG. 5, the upper and lower molds 7 and 8 are fitted into the mold 7a of the lower mold 7 in a bent shape, and then the upper mold 8 is used to fit the molds into the molds 7 and 8. So.

cent. In this set state, one end of the rubber tube 5 is in a state of protruding to the outside of the molds 7 and 8.

When the setting of the cylindrical wound article in the molds 7 and 8 is completed as described above, a preheating process is performed using a heater (not shown). This preheating treatment brings the resin 3 of the prepreg sheet 4 into a fluid state. When the resin 3 is in a fluid state in this way, compressed air is blown into it from one end of the rubber tube 5 protruding from the mold 7.degree. 8, and heat curing treatment is performed while continuing this blowing state.

By blowing the compressed air, the resin 3, which has become fluid due to the preheating treatment, moves toward the outer surface of the cylindrical roll and expels the air contained inside. Therefore, a molded product having a clean surface without voids is formed.

FIG. 2 is a tubular molded body showing another embodiment of the present invention.

This tubular body 10 has a diameter that changes in the length direction, and is used as a baseball bat, a golf club shaft, or the like. This tubular body 10 also corresponds to the tubular body 1 shown in FIG.
Similarly, reinforcing material such as carbon fiber cut into short fibers m
It is integrally molded and cured from a prepreg sheet consisting of a fiber 2 and a thermosetting resin such as an epoxy resin impregnated into the reinforcing fiber 2, and the reinforcing fiber 2 in the form of short fibers is arranged randomly throughout the molded body. ing.

The above-mentioned tubular bodies 1.10 each have a large number of reinforcing fibers 2 in the form of short fibers with random directions wound into a tubular shape, so that the entire molded body has uniform directionality and fiber density. have. Therefore, the tubular body 1,
Although the bent shape and diameter of No. 10 change in the longitudinal direction, the molded article can exhibit high uniformity of strength and isotropy over the entire molded article.

〔Effect of the invention〕

As described above, the tubular molded body of the present invention is a tubular body that has a bent shape or has a diameter that changes in the length direction,
The tubular body is formed from a sheet-like material in which short reinforcing fibers impregnated with thermosetting resin are randomly dispersed. By using randomly arranged short reinforcing fibers, it is possible to obtain high strength uniformity and isotropy over the entire molded product.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a bent tubular body that is an embodiment of the present invention, FIG. 2 is a perspective view of a tubular body with a changed diameter that is another embodiment of the present invention, and FIGS. Fig. 3 is a plan view showing an example of a prepreg sheet used to form the bent tubular body, and Fig. 4 is a method for winding the prepreg sheet around a rubber tube. FIG. 5 is a perspective view showing the situation during rolling, and FIG. 5 is a perspective view showing the state in which the cylindrical wound product after being wound is placed in a mold. 1.10... Tubular body, 2... Reinforcing fiber, 3...
・Thermosetting resin, 4...prepreg sheet.

Claims (1)

[Claims] A tubular body that has a bent shape or a diameter that changes in the length direction, and the tubular body is formed from a sheet-like material in which short reinforcing fibers impregnated with a thermosetting resin are randomly dispersed. A tubular molded body characterized by: