JPS6350436A - Method for manufacturing reinforcing cylindrical fiber molded product - Google Patents

Abstract

PURPOSE:To prevent cracking and deterioration in dimensional accuracy of a fibrous molded body, by pushing a molded-body material against a pattern to arrange the shape of the above material, by heating the pattern up to a collapse temp. or above to remove the pattern, and then by burning the above material so as to bind with an inorganic binder. CONSTITUTION:The fibrous molded body 1 is formed by binding a fiber reinforcement (a fibrous mixture of carbon fiber and alumina fiber) with an inorganic binder (silica sol, etc.). The outside periphery of the pattern 2 is covered with a thin-film body F to be burnt down at collapse temp., and the openings at both ends of the pattern are hermetically sealed by means of holders 31, 32. Subsequently, the pattern 2 is immersed in an aqueous solution 4 of the molding material, and the molded-body material 6 is formed on the outside periphery of the pattern 2 by suction with a vacuum pump 5. The pattern 2 is placed in a pressure vessel 9 and pressurized to undergo shape arrangement of the molded-body material 6. Then low-temp. heating is applied so as to let the thin-film body F disappear and, after that, the pattern 2 is collapsed by means of heating up to the collapse temp. or above, so that molded-body material 6 can be formed. In this way, deformation of the molded-body material is prevented and dimensional accuracy can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION A0 OBJECTS OF THE INVENTION (1) Industrial Field of Use The present invention relates to a method for manufacturing a reinforcing cylindrical fiber molded body used when reinforcing metal members or the like with fibers.

(2) Conventional technology Conventionally, this type of fiber molded article was produced by sealing the openings at both ends of a cylindrical mold with air permeability, and immersing the mold in an aqueous solution of a molding material containing reinforcing fibers and an inorganic binder. , a process of applying a suction action within the mold to make the molding material adhere to the outer peripheral surface of the mold to form a molded body material, a process of pressing the molded body material against the mold to adjust the shape of the molded body material , a process of opening both end openings of the mold and pulling the mold from the molded body material, a process of heating and drying the molded body material, and a process of firing the molded body material and partially bonding the reinforcing fibers with an inorganic binder. Manufactured through a process.

(3) Problems to be Solved by the Invention However, when the mold is pulled out from the molded body material before the molded body material is heated and dried as described above, the molded body material contains a large amount of water and loses its shape. Because of the poor properties, there is a problem that the molded body material is deformed and the dimensional accuracy of the fiber molded body is deteriorated.

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

B0 Structure of the Invention +11 Means for Solving Problems The present invention seals the openings at both ends of a cylindrical mold with air permeability that can be collapsed under high temperature heating, and makes the outer peripheral surface of the mold air permeable. and covered with a thin film that is completely burned out at the collapse temperature of the mold,
The mold is immersed in an aqueous solution of a molding material containing reinforcing fibers and an inorganic binder, and a suction action is applied within the mold to cause the molding material to adhere to the outer peripheral surface of the mold via the thin film body. a step of molding the molded body material; a step of pressing the molded body material into the mold to adjust the shape of the molded body material; heating and drying the molded body material at a temperature lower than the collapse temperature of the mold. a step of heating the mold to a temperature higher than its collapse temperature to completely burn out the thin film body and collapsing and removing the mold; firing the molded material to remove the reinforcing fibers with the inorganic binder; It is characterized by using a step of partially bonding;

(2) Effect When the mold is disintegrated and removed after heating and drying the molded body material as described above, deformation of the molded body material can be prevented and the dimensional accuracy of the fiber molded body can be improved. The drawing process can be omitted.

Furthermore, although the mold expands during heating and drying of the molded body material, the amount of expansion is absorbed by the buffering effect of the thin film, and even at the collapse temperature of the mold, the mold expands prior to its collapse. Since the amount of expansion is absorbed by the voids formed by complete burning of the thin film body, cracks caused by the expansion of the mold do not occur in the molded body material.

Furthermore, since the molded body material is in contact with the mold through the thin film, the constituent materials will not adhere to and remain on the molded body material after the mold collapses, and therefore the inner circumferential surface of the molded body material will be smooth. becomes.

(3) Example Figure 1 shows a reinforcing cylindrical fiber molded article 1 obtained according to the present invention.
The fiber molded article 1 is made by partially bonding mixed short fibers of carbon fibers and alumina fibers as reinforcing fibers with silica sol, alumina sol, or a mixed sol thereof as an inorganic binder, and the fiber molded body 1 is made of a mixture of short fibers of carbon fiber and alumina fiber as reinforcing fibers, and is partially bonded with silica sol, alumina sol, or a mixed sol thereof as an inorganic binder, and the matrix is infiltrated. It has countless voids that can be removed.

This fiber molded body 1 is used, for example, in order to obtain a fiber-reinforced composite cylinder sleeve by combining with an aluminum alloy matrix when casting an aluminum alloy cylinder block.

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

As shown in Figure 2 (a+), shell sand (grain size AFS35
) is used to form a cylindrical mold 2 having air permeability.

This mold 2 has an outer diameter of 75 mm, a thickness of about 5 mm, and a radial crushing strength of 65 kir/-. Furthermore, since the mold 2 is made of shell sand, it has the property of collapsing when heated to a high temperature of 350 to 400°C.

In addition, the entire outer circumferential surface of the mold 2 is covered with a thin film material, such as 6
- Covered with a stockinette-knit stretchable thin fabric F made of nylon with a thickness of 0.10*m.

As shown in FIG. 2 (bl), holders 36 and 3□ are attached to the openings at both ends of the mold 2 by adhesive, bolting, etc., and the openings are sealed.

FIG. 2 (As shown in C1, an aqueous solution 4 of a molding material containing mixed fibers of carbon fibers and alumina fibers and alumina sol)
The mold 2 is immersed in the mold 2, and the vacuum pump 5 applies suction to the inside of the mold 2 to make the molding material adhere to the outer peripheral surface of the mold 2 through the thin cloth F to a predetermined thickness. to form. This molding operation using the vacuum pump 5 is performed for approximately 2 minutes.

As shown in FIG. 2+dl, the mold 2 is placed in the pressure container 7 of the rubber press, and pressurized air is supplied from the air pressure source 8 into the pressure container 7 to form the molded material 6 through the rubber 9. The outer peripheral surface of the mold 2 is pressed with a pressure of 10 kg/ad, thereby adjusting the shape of the molded body material 6 and determining the density at the same time.

In this case, the diameter of the mold 2 is slightly reduced due to the pressing force, but since the thin fabric F follows the shrinking action by its shrinking action, wrinkles do not occur in the thin fabric F. It is possible to prevent roughening of the inner circumferential surface of the molded body material 6 due to the transfer. After the pressing force is released, the mold 2 is restored to its original state, but since the thin fabric F is stretched at this time, no problem occurs.

FIG. 2 (As shown in Ql, both holders 32 are removed from the mold 2.
, Remove 3□.

As shown in FIG. 2 (fl), the mold 2 is placed in a drying oven 10, and the molded body material 6 is subjected to a drying process at 120° C. for 1 hour to remove moisture once. This heating drying process The thin fabric F starts to burn out inside the mold.Also, the mold 2 expands, but the amount of expansion is absorbed by the void created by partially burning the thin fabric F and the cushioning effect of the remaining thin fabric F. Therefore, cracks due to expansion of the mold 2 do not occur in the molded body material 6.

As shown in FIG. 2(g), the mold 2 is placed 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 the temperature is increased. Thin cloth F is completely burned out in the process. By this disintegration process, the mold 2
Approximately 50% of it collapses. The remaining approximately 50% is destroyed and removed by means such as applying vibration, but under this condition, the molded body material 6 is dried and has sufficient shape retention, so it will not deform. Further, since numerous cranks and the like are generated in the remaining portion of the mold 2, they can be easily removed.

Even at the collapse temperature of the mold 2, the mold 2 expands before collapsing, but the amount of expansion is absorbed by the voids g generated as the thin fabric F is burned out, and therefore, as described above, the mold material 6 No cracks will occur.

Furthermore, since the molded body material 6 is in contact with the mold 2 through the thin cloth F, shell sand, which is the constituent material of the mold 2, does not adhere to and remain on the molded body material 6 after the mold 2 collapses. The inner peripheral surface of the molded body material 6 becomes smooth.

As shown in FIG. 2 [h], only the molded body material 6 is placed in the firing furnace 11, and the molded body material 6 is heated to 800°C.
A firing treatment is performed for a period of time, whereby the mixed fibers are partially bonded by the alumina sol and a fiber molded body 1 shown in FIG. 1 is obtained.

In the disintegration process of the mold 2, the mold 2 is 100%
In order to collapse the thickness, the thickness should be reduced to approximately half that of the above example.
．． The thickness may be about 5 m, but if it is formed so thinly, the strength will be weakened and there is a risk that the mold 2 will be destroyed during the molding process of the molded body material and the rubber pressing process. By setting the thickness of the mold 2 to approximately 51 mm as in the above embodiment, the mold 2 can be prevented from being destroyed during the molding process of the molded body material, and approximately 50% collapse can be achieved through the collapse treatment. Can be done.

Note that as the thin film body, it is also possible to use breathable thin paper or the like in addition to thin cloth.

C1 Effect of the Invention According to the present invention, a mold that can be disintegrated under high temperature heating is used, and the mold is disintegrated and removed after heating and drying the molded body material, thereby preventing deformation of the molded body material and producing a fiber molded body. The dimensional accuracy of the mold can be improved, and the production efficiency can be improved by omitting the step of drawing out the mold.

Moreover, by interposing a thin film between the molded body material and the mold, which is completely burned out at the collapse temperature of the mold,
It is possible to prevent the occurrence of cracks in the molded body material due to thermal expansion of the mold, and also to prevent the mold constituent materials from remaining attached to the molded body material, thereby obtaining a high quality fiber molded body.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a fiber molded product, and FIG. 2 is an explanatory diagram of the manufacturing process of the fiber molded product. F...Thin cloth as a thin film body,

Claims (1)

[Claims] The openings at both ends of a cylindrical mold with air permeability that can be collapsed under high temperature heating are sealed, and the outer peripheral surface of the mold has air permeability,
The mold is covered with a thin film that completely burns out at the collapse temperature of the mold, and the mold is immersed in an aqueous solution of a molding material containing reinforcing fibers and an inorganic binder, and a suction action is applied to the inside of the mold. a step of attaching a material to the outer peripheral surface of the mold through the thin film body to form a molded body material; a step of pressing the molded body material against the mold to adjust the shape of the molded body material; a step of heating and drying the molded body material at a temperature lower than the collapse temperature of the mold; a step of heating the mold to a temperature higher than the collapse temperature to completely burn out the thin film body and collapsing and removing the mold; A method for manufacturing a reinforcing cylindrical fiber molded body, comprising: firing the molded body material and partially bonding the reinforcing fibers with the inorganic binder.