JP2948434B2 - Method and apparatus for forming composite material blade - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for molding a composite material blade using a resin injection molding method. In the process of injecting a resin and causing excess resin to flow out from an outlet, bubbles are generated in the discharged resin. The present invention relates to a method and an apparatus for forming a composite material blade having a high-quality formed layer with less residual air bubbles by repeating discharge and cutoff until the resin is no longer contained.

[0002]

2. Description of the Related Art Blades such as propeller blades for aircraft, turbofan blades, helicopter blades, and general industrial rotor blades are sometimes made of composite materials such as FRP instead of conventional metals. In the method of molding a composite material blade, generally, a blade insert having reinforcing fibers attached to the surface is inserted between a mold for molding the abdominal surface of the blade and a mold for molding the back surface, and the mold is squeezed, and a thermosetting resin is formed. A resin injection molding method is employed in which excess resin is allowed to flow out of an outlet while being injected, and then heated to a required temperature or further maintained for a required time to solidify and mold the resin.

[0003]

In the conventional resin injection molding method, air bubbles often remain when a reinforcing fiber is impregnated with a resin. The cause is that due to the variation in the density distribution of the reinforcing fibers, uneven portions of the flow resistance of the resin in the molding die are generated, and there is a portion where the resin easily flows and a portion where the resin does not easily flow and stays. . If a portion of the resin containing air bubbles stays, no matter how much resin is injected and then replaced, the new resin flows through the above-mentioned passage where the resin easily flows, and the problem that the resin cannot be replaced effectively there were.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of forming a composite material blade having a high-quality formed layer with few residual bubbles in a method of forming a composite material blade using a resin injection molding method, and an object thereof.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a blade insert having reinforcing fibers attached to the surface thereof is inserted between a mold for molding the abdominal surface of the blade and a mold for molding the back surface thereof, and the mold is squeezed and heat-cured. In the method of molding a composite material blade using a resin injection molding method in which excess resin is allowed to flow out of an outlet while injecting a conductive resin and then solidified, the outlet is shut off when the resin is injected, and the excess resin is discharged after a predetermined time. Is repeated until no air bubbles are contained in the discharged resin.

According to a second aspect of the present invention, there is provided a resin injection molding apparatus comprising a molding die provided with a resin injection port and a discharge port. The composite blade is characterized in that the valve has a closing / opening valve control means for repeating a shut-off and conduction cycle in which the valve is opened and the excess resin is discharged after holding the valve for a predetermined time to discharge the excess resin in a previously programmed step. It is a molding device.

[0007]

The operation of the method for forming a composite material blade according to the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view showing the configuration of a composite material blade forming apparatus according to the present invention. FIG.
FIG. 2 is an explanatory cross-sectional view taken along line AA of the molding die of FIG. 1. A resin injection port 2 and a discharge port 3 are provided in a molding die 1 of the molding apparatus, and an injection pipe 5 from a resin pressure feeding tank 4 is provided in the resin injection port 2.
And a resin reservoir container 7 is connected to the outlet 3 through a conduit 6.
The on-off valve 8 is attached in the middle of the conduit 6, and the on-off valve 8 is configured to be controlled by a valve controller 9.

[0008] In forming, first, the blade insert 1
The reinforcing fiber 11 is attached to the mold 0, and is loaded into the cavity 1c of the molding die 1, and the dies 1a and 1b are closed. The piston 4a of the resin pressure feeding tank 4 is pushed down, and the resin in the tank is injected into the molding die 1 from the injection port 2 via the injection pipe 5. Resin flows the gap walls and blade insert 10 of the cavity 1c, the gap flows slowly so as to penetrate the reinforcing fibers 11 because they are filled with reinforcing fibers 11. Due to the variation in the density of the reinforcing fibers 11, the flow resistance of the gap varies depending on the location in the molding die 1, and places where the resin easily flows and where the resin hardly flows are formed.

Therefore, even if the injection is continued for a long time, the resin tends to form a steady passage at a place where the resin easily flows and drift. On the other hand, places where flow is difficult form a steady pool. Further, it is difficult to discharge the air bubbles generated at the beginning of the injection when the resin is rolled up to form a pool, and when the resin is cured as it is, a molded article containing residual air bubbles is obtained. Here, if the opening / closing operation of the on-off valve 8 is added, the steady flow path distribution can be destroyed, and such a pool is discharged. However, after a while, the operation becomes steady again, so that the opening and closing operation needs to be performed repeatedly.

That is, the flow of the resin in the molding die 1 steadily includes a portion (passage) that easily flows and a portion (pool) that hardly flows, and a pressure difference is locally generated in the die 1. However, when the on-off valve 8 is closed, the resin flow stops,
It works so that the pressure difference in the mold 1 is also eliminated. When the on-off valve 8 is opened in anticipation of the time when the pressure in the mold 1 has become uniform, the resin in the flowable portion flows when the opening / closing valve 8 is opened. As a result, bubbles trapped in the pool are discharged. However, the flow distribution becomes steady again after flowing for a while, so that the closed flow path can be broken by closing the on-off valve 8 again. The opening and closing of the on-off valve 8 is performed by the valve controller 9, and the opening and closing intervals are appropriately selected according to the molding die, the shape of the material to be molded, the type of resin, and the like.

[0011]

EXAMPLE Using a molding apparatus according to the present invention as shown in FIG. 1, a composite material blade was molded using carbon fiber as the reinforcing fiber and epoxy resin as the resin. At the time of resin injection, the on-off valve is closed to shut off the discharge port, and after holding for 5 minutes, the on-off valve is opened to discharge excess resin for 10 minutes. This was repeated until no air bubbles were contained, and then the resin was cured by heating and holding to complete the molding. Further, when the same composite material blade was formed by a conventional resin injection molding method having no on-off valve in the discharge system, a plurality of air bubble traces were observed on the blade surface layer. On the other hand, in the molding method according to the present invention described above, there was no trace of bubbles on the surface layer, and a high-quality composite material blade was obtained.

[0012]

According to the present invention, in a method of molding a composite material blade using a resin injection molding method, a step of shutting off a discharge port at the time of resin injection and discharging a surplus resin after a predetermined time is repeated, whereby the resin is molded. The hard-to-flow portion (pool), that is, the steady flow path can be destroyed, and the discharge of bubbles remaining in the mold until the discharge resin no longer contains bubbles reduces the molding time and reduces residual bubbles. It is possible to form a composite blade with less
A remarkable effect can be obtained for improving the quality of the composite material blade.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a composite material blade forming apparatus according to the present invention.

FIG. 2 is an explanatory cross-sectional view taken along line AA of the molding die of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molding mold 1a, 1b Mold cavity 1c cavity 2 Injection port 3 Discharge port 4 Resin pumping tank 5 Injection pipe 6 Conduit 7 Resin storage container 8 On-off valve 9 Valve controller 10 Blade insert 11 Reinforcing fiber

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B64C 11/20 B64C 3/24

Claims (2)

(57) [Claims] 1. A blade insert having reinforcing fibers attached to the surface thereof is inserted between a mold for molding the abdominal surface of the blade and a mold for molding the back surface thereof, and the mold is squeezed. In a molding method of a composite material blade using a resin injection molding method in which a resin flows out from a discharge port and then solidifies, a step of shutting off a discharge port at a time of resin injection and discharging a surplus resin after a predetermined time is performed on a discharged resin. A method for forming a composite material blade, which is repeated until no bubbles are contained. 2. A resin injection molding apparatus comprising a molding die having a resin injection port and a discharge port, wherein an on-off valve is provided in a conduit between the discharge port and the resin reservoir, and the valve is closed when the resin is injected. An apparatus for forming a composite material blade, comprising a control means for an on-off valve for repeating a shut-off and conduction cycle in which a valve is opened after a time is held to discharge excess resin in a previously programmed step.