JPH0668140B2 - Method for manufacturing tubular fiber molding for reinforcement - Google Patents

Description

Detailed Description of the Invention A. OBJECT OF THE INVENTION (1) Field of Industrial Application The present invention relates to a method for producing a reinforcing tubular fiber molded body that is used when fiber-reinforced a metal member or the like.

(2) Conventional technology Conventionally, this kind of fiber molded body seals the openings at both ends of a cylindrical mold having air permeability, and immerses the mold in an aqueous solution of a molding material containing a reinforcing fiber and an inorganic bainda. , A step of adhering a molding material to the outer peripheral surface of the molding die by applying a suction action to the molding die to mold the molding material, and a step of pressing the molding material against the molding die to adjust the shape of the molding material , Opening both ends of the mold, pulling out the mold from the molded material, heating and drying the molded material, and calcining the molded material to partially bond the reinforcing fibers with the inorganic binder. It is manufactured through steps.

(3) Problems to be Solved by the Invention However, as described above, when the molding die is pulled out from the molded body material before heating and heating of the molded body material, the molded body material contains a large amount of water and retains its shape. Since the property is poor, there is a problem that the material of the molded body is deformed and the dimensional accuracy of the fiber molded body is deteriorated.

It is an object of the present invention to provide the above manufacturing method capable of solving the above problems.

B. Structure of the Invention (1) Means for Solving the Problems The present invention is to seal both end openings of a cylindrical mold having air permeability capable of collapsing under high temperature heating, and to make the outer peripheral surface of the mold air-permeable. And is covered with a thin film body that is completely burned at the mold collapse temperature, the mold is immersed in an aqueous solution of a molding material containing reinforcing fibers and an inorganic binder, and suction is applied to the mold. Thereby adhering the molding material to the outer peripheral surface of the molding die through the thin film body to mold a molding material, and pressing the molding material against the molding die to adjust the shape of the molding material. A step of heating and drying the molded body material at a temperature lower than the collapse temperature of the molding die;
Heating the mold to a collapse temperature or higher to completely burn off the thin film body and to collapse and remove the mold;
A step of firing the molded body material to partially bond the reinforcing fibers with the inorganic binder.

(2) Action When the molding die is disintegrated and removed after heating and drying the molded body material as described above, it is possible to prevent deformation of the molded body material and improve the dimensional accuracy of the fiber molded body. It is possible to omit the drawing process.

In addition, the mold expands during the heat-drying of the molded body material, but the expansion amount is absorbed by the buffering effect of the thin film body,
Further, even at the collapse temperature of the mold, the mold expands prior to the collapse, but the expansion amount is absorbed by the voids formed by the complete burning of the thin film body,
No cracks due to expansion of the mold are generated.

Furthermore, since the molded body material is in contact with the molding die through the thin film body, the constituent material does not adhere to and remain on the molded body material after the molding die collapses, and thus the inner peripheral surface of the molded body material is smooth. Becomes

(3) Example FIG. 1 shows a tubular fiber molding for reinforcement 1 obtained by the present invention.
The fiber molded body 1 is obtained by partially binding mixed short fibers of carbon fibers and alumina fibers as reinforcing fibers with silica sol, alumina sol as an inorganic binder, or a mixed sol thereof, and the matrix is infiltrated. It has a myriad of possible voids.

This fiber molded body 1 is used for obtaining a fiber-reinforced composite cylinder sleeve by being compounded with an aluminum alloy matrix when casting an aluminum alloy cylinder block, for example.

Next, a method for manufacturing the fiber molded body 1 will be described with reference to FIG.

As shown in Fig. 2 (a), shell sand (grain size AFS35)
Is used to form a cylindrical mold 2 having air permeability. The mold 2 has an outer diameter of 75 mm, a thickness of about 5 mm, and a radial crushing strength of 65 kg / cm ² . Further, since the mold 2 is made of shell sand, it has a property of disintegrating when heated to a high temperature of 350 to 400 ° C.

In addition, the entire outer peripheral surface of the molding die 2 is a thin film body having air permeability and completely burned down at the collapse temperature of the molding die 2, for example, 6
-A thick 0.10 mm nylon cloth covered with a stretchy thin cloth F knitted.

As shown in FIG. 2 (b), holders 3 ₁ and 3 ₂ are attached to the openings of both ends of the molding die ₂ by bonding, bolting or the like to seal the openings.

As shown in FIG. 2 (c), the molding die 2 is immersed in an aqueous solution 4 of a molding material containing a mixed fiber of carbon fibers and alumina fibers and alumina sol, and a suction action is applied into the molding die 2 by a vacuum pump 5. Then, the molding material is attached to the outer peripheral surface of the molding die 2 with a predetermined thickness through the thin cloth F, and the molding material 6 is molded. The molding operation by the vacuum pump 5 is performed for about 2 minutes.

As shown in FIG. 2 (d), the molding die 2 is installed in a pressure resistant container 7 of a rubber press, and pressurized air is supplied from the air pressure source 8 into the pressure resistant container 7 to form a molded material through the rubber 9. Mold 2 for 6
The outer peripheral surface is pressed with a pressure of 10 kg / cm ² , whereby the shape of the green body material 6 is adjusted and the density is determined at the same time.

In this case, the molding die 2 slightly contracts in diameter due to the pressing force, but since the thin cloth F follows the contracting action due to its contracting action, wrinkles do not occur in the thin cloth F, and therefore wrinkles do not occur. It is possible to prevent the inner peripheral surface of the molded body material 6 from being roughened by the transfer of. After the pressing force is released, the molding die 2
Is restored to its original state, but at this time, since the thin cloth F stretches, there is no problem.

As shown in FIG. 2 (e), both holders 3 ₁ ,
3 ₂ Remove the.

As shown in FIG. 2 (f), the molding die 2 is installed in the drying furnace 10, and the molding material 6 is subjected to a drying treatment at 120 ° C. for 1 hour to remove water by evaporation. The thin cloth F starts to burn out during this heating and drying process. Further, the molding die 2 expands, but the expansion amount is absorbed by the voids generated by the partial burning of the thin cloth F and the cushioning action of the remaining thin cloth F, so that the molding material 6 expands the molding die 2 by expansion. Does not cause cracks.

As shown in FIG. 2 (g), the mold 2 is installed in the firing furnace 11, and the mold 2 is subjected to a disintegration treatment for 1 hour at a temperature of 350 to 400 ° C. or higher, and its temperature is raised. In the process, the thin cloth F is completely burned out. About 50% of the mold 2 collapses by this collapse treatment. The remaining approximately 50% is destroyed and removed by means such as applying vibration, but in this state, the molded body material 6 is dried and has sufficient shape retention, so that it does not deform, Further, since cracks and the like are numerous in the remaining portion of the molding die 2, the removal thereof can be easily performed.

Even at the collapse temperature of the molding die 2, the molding die 2 expands before the collapse, but the expansion amount is absorbed by the void g generated by the burning of the thin cloth F, and thus the molding material 6 as described above. There will be no cracks.

Further, since the molded body material 6 is in contact with the molding die 2 through the thin cloth F, after the collapse of the molding die 2, the shell sand which is the constituent material thereof does not adhere to the molded body material 6 and remain there. The inner peripheral surface of the molded body material 6 becomes smooth.

As shown in FIG. 2 (h), only the green body material 6 is placed in the firing furnace 11 this time, and the green body material 6 is subjected to firing treatment at 800 ° C. for 1 hour. As a result, the mixed fibers are partially bonded by the alumina sol and the fiber molded body 1 shown in FIG.
Is obtained.

In the disintegration process of the mold 2, the mold 2 is 100%
In order to disintegrate, the thickness is about half of that in the above example 2.
The thickness may be about 5 mm, but if it is formed thin like this, the strength is weakened and the mold 2 may be destroyed in the forming step of the green body material and the rubber pressing step. By setting the thickness of the molding die 2 to about 5 mm as in the above embodiment, it is possible to prevent the molding die 2 from being broken in the molding process of the molded body material and to achieve a collapse of about 50% by the collapse treatment. You can

In addition, as the thin film body, it is also possible to use thin paper having air permeability or the like in addition to a thin cloth.

C. EFFECTS OF THE INVENTION According to the present invention, a mold capable of collapsing under high-temperature heating is used, and the mold is disintegrated and removed after heating and drying the molded body material. The dimensional accuracy can be improved, and the production efficiency can be improved by omitting the mold drawing process.

Moreover, by interposing a thin film body that completely burns down at the collapse temperature of the mold between the molded body material and the mold,
It is possible to prevent the generation of cracks in the molded body material due to the thermal expansion of the molding die, and prevent the molding die material from remaining on the molded body material.

[Brief description of drawings]

FIG. 1 is a perspective view of a fiber molded body, and FIG. 2 is an explanatory view of a manufacturing process of the fiber molded body. F ... Thin cloth as a thin film body, 1 ... Fiber molding, 2 ... Mold, 4 ... Aqueous solution of molding material,
5 ... Vacuum pump, 6 ... Molded material, 8 ... Air pressure source, 10 ...
Drying furnace, 11 ... Baking furnace

Claims (1)

[Claims] 1. A tubular molding die having a breathability capable of collapsing under heating at a high temperature is hermetically sealed at both end openings, has an air permeability on the outer peripheral surface of the molding die, and is perfect at the collapse temperature of the molding die. The mold is covered with a thin film body that burns down, the mold is immersed in an aqueous solution of a mold material containing reinforcing fibers and an inorganic binder, and a suction action is applied to the mold to form the mold material through the thin film body. A step of adhering to the outer peripheral surface of the mold to form a molded body material; a step of pressing the molded body material against the molding die to adjust the shape of the molded body material; a collapse of the molded body material into the molding die A step of heating and drying at a temperature lower than the temperature; a step of heating the forming die to a disintegration temperature or higher to completely burn off the thin film body and disintegrating and removing the forming die; Part of the reinforcing fiber by the inorganic binder Process and to bind to, according to the method of manufacturing a reinforced tubular fiber molding which comprises using a.