JPS63199835A - Forming apparatus for cylindrical fibrous formed body for reinforcement - Google Patents

Abstract

PURPOSE:To manufacture a cylindrical fibrous formed body for reinforcement, by forming an air-permeable cylindrical body of shell molding sand, by covering the outside periphery with a thin-air-permeable film, by making a mixture of carbon fiber, alumina fiber, and alumina sol to be adsorbed by the surface of the cylindrical body, by drying and heating the above to collapse the cylindrical body, and then by carrying out sintering in an inert gas. CONSTITUTION:An air-permeable cylindrical body 2 is formed of shell molding and, the whole outside-perpheral surface is covered with air-permeable stretchable thin cloth F, and both ends are hermetically sealed with holders 31, 32. Subsequently, the above cylindrical body 2 is placed in a tank 5 filled with an aqueous solution containing forming material containing carbon fiber, alumina fiber, and alumina sol and is sucked from a hole 7 of the holder 32 by means of a pump 6 so as to form a fibrous formed body 1 on the outside peripheral surface of the cylindrical body 2. The above cylindrical body is placed in a pressure vessel 8 and pressurized by means of an air pressure source 9 to arranged the shape of the fibrous formed body 1, and, after both holders 31, 32 are removed, the above cylindrical body is dried in a drying furnace and the thin cloth F is incinerated. Successively, the above cylindrical body is placed in a burning furnace 12, where heating up to 330-480 deg.C is applied so as to collapse the cylindrical body 2 made of shell sand. In this way, the cylindrical fibrous formed body for reinforcement in which the fibrous formed body composed of both fibers is bound with alumina sol can be manufactured.

Description

Detailed Description of the Invention A9 Object of the Invention (1) Industrial Application Field The present invention relates to a molding apparatus for a reinforcing cylindrical fiber molded article, in particular, a tank containing an aqueous solution of a molding material containing reinforcing fibers, and a tank at both ends. A breathable cylindrical mold with an opening sealed and placed upright in the tank, and applying a suction action within the mold to adhere the molding material in an agitated state to the outer peripheral surface of the mold. The present invention relates to an improvement in a device equipped with a suction mechanism for

(2) Prior Art Conventionally, this type of device has been configured to stir a molding material by rotating a stirring blade disposed in a tank.

(3) Problems to be Solved by the Invention In the conventional device described above, in order to sufficiently stir the molding material, it is sufficient to increase the rotational speed of the stirring blade to form a spiral flow of the molding material. If this is done, the molding material will flow rapidly along the outer periphery of the mold, resulting in poor adhesion of the molding material to the mold, and the adhered molding material will be removed by the flow. The production efficiency is poor, and it is difficult to obtain a fiber molded product having a uniform thickness.

In view of the above, an object of the present invention is to provide an apparatus capable of improving production efficiency of fiber molded bodies and obtaining fiber molded bodies having a uniform thickness.

B0 Structure of the Invention (11 Means for Solving Problems) The present invention comprises a tank containing an aqueous solution of a molding material containing reinforcing fibers, and an air permeable cylinder that is erected in the tank with both end openings sealed. A molding device for a reinforcing cylindrical fiber molded body, comprising a shaped mold and a suction mechanism that applies suction to the inside of the mold to cause the molding material in an agitated state to adhere to the outer peripheral surface of the mold. The mold is disposed immovably within the tank, and the tank is configured to be rotatable around the axis of the mold, and the mold is provided with a mold extending in the axial and radial directions around the mold. A plurality of straightening plates are arranged immovably, and a plurality of first stirring plates arranged at intervals in the inner circumferential surface generatrix direction of the tank and in the □ circumferential direction are arranged such that the lower edge of each first stirring plate is connected to the tank. a plurality of second stirring plates provided on the inner peripheral surface of the tank so as to be inclined so that their upper edges are located on the front side in the rotational direction and on the rear side in the tank rotational direction, and whose inclination relationship is opposite to that of each first stirring plate; The present invention is characterized in that a stirring plate is provided on each rectifying plate so as to overlap the rotation locus of each 1ft! stirring plate.

(2) Effect When configured as described above, the molding material is stirred near the inner circumferential surface of the tank by each of the first and second g & stirring parts, and this stirring action causes the flow of the molding material to become turbulent. state. This prevents the molding material from stagnating at the bottom of the tank and allows sufficient stirring.

When the flow of the molding material collides with each rectifying plate, the flow velocity is weakened, and also because of the suction effect inside the mold, the flow becomes a laminar flow toward the outer peripheral surface of the mold. This improves the adhesion of the molding material to the mold, and the adhered molding material is hardly removed by the flow.

(3) Example FIG. 1 shows a reinforcing cylindrical fiber molded body l obtained through a molding process, a drying process, a firing process, etc. using the apparatus of 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 fibers and alumina fibers as reinforcing fibers, and is partially bonded with silica sol, alumina sol, or a mixed sol thereof as an inorganic binder. It has a void of.

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. In this case, carbon fiber mainly improves the sliding characteristics of the inner peripheral surface of the cylinder sleeve due to its lubricating ability.
Furthermore, the alumina fibers mainly contribute to improving the strength around the cylinder bore.

The fiber molded body 1 is obtained through the manufacturing process shown in FIG.

In Fig. 2fa), the mold 2 is made of shell sand (grain size AF
S35) is formed into a cylindrical shape with air permeability, and has the property of completely collapsing when heated to 330 to 480°C.

First, the entire outer peripheral surface of the mold 2 is covered with a thin film body that has air permeability and completely burns out at the collapse temperature of the mold 2, for example,
Covered with a stockinette-knit stretchable thin fabric F made of 6-nylon and having a thickness of 0.10 m.

As shown in FIG. 2(b), holders 3+ and 3t are attached to the openings at both ends of the mold 2 by bonding, bolting, etc., and the openings are sealed.

As shown in FIG. 2 (C1), a mold 2 is placed in a cylindrical tank 5 of a molding device 4 containing an aqueous solution of a molding material containing mixed fibers of carbon fibers and alumina fibers, alumina sol, etc.
is set upright, and the holder 3. applying suction through the opening 7 of the
The molding material is applied to the outer circumferential surface of the mold 2 via the thin cloth F to a predetermined thickness, and the fiber molded body 1 is molded. This molding operation using the water pump 6 is performed for approximately 2 minutes.

As shown in FIG. 2(d), the mold 2 is placed in a pressure container 8 of a rubber press, and pressurized air is supplied from an air pressure source 9 into the pressure container 8 to form a fiber molded product through the rubber lO. 1 is pressed against the outer circumferential surface of the mold 2 with a pressure of 10 kg/J, thereby adjusting the shape of the fiber molded product 1 and determining the fiber volume fraction 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. Roughening of the inner circumferential surface of the fiber molded body 1 due to the transfer can be prevented. 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.

As shown in Fig. 2 (el), both holders 31 are removed from the mold 2.
．． 3 Remove □.

As shown in FIG. 2(f), the mold 2 is placed in a drying oven 11 maintained in an air atmosphere, and the fiber molded body 1 is dried for 60 minutes at an oven temperature of 120°C to remove moisture. is removed by evaporation. During this heat drying process, the thin fabric F starts to burn out. Furthermore, although the mold 2 expands, the amount of expansion is absorbed by the voids created by partially burning out the thin fabric F and the buffering effect of the remaining thin fabric F. Cracks caused by this will not occur.

As shown in FIG.
A disintegration treatment is performed at 50° C. for 30 minutes, and the thin fabric F is completely burned out during the temperature rising process. The mold 2 is 100% collapsed by this collapse treatment.

The mold 2 expands before collapsing, but the amount of expansion is absorbed by the void g generated as the thin fabric F is burned out, and therefore, similar to the above, cranks do not occur in the fiber molded product L. do not have.

Furthermore, since the fiber molded body 1 is in contact with the mold 2 through the thin cloth F, the shell sand, which is the constituent material of the mold 2, does not adhere to and remain on the fiber molded body l after the mold 2 collapses. The inner peripheral surface of the fiber molded body 1 becomes smooth.

As shown in FIG. 2(h), this time only the fiber molded body 1 was placed in a firing furnace 12 maintained in an argon atmosphere, and the fiber molded body 1 was fired for 30 minutes at a furnace temperature of 800°C. A treatment is applied to partially bond the mixed fibers with alumina sol. In this case, since the firing process is performed in an argon atmosphere, oxidation of the carbon fibers is avoided and their weight loss is prevented. Note that other inert gases may be used instead of argon.

Next, the molding device 4 will be explained in detail with reference to FIGS. 3 to 5.

The tank 5 that accommodates the aqueous solution of the molding material has an open top surface and a hollow shaft portion 13 on the outer surface of the bottom. Supported by In order to erect the mold 2 in the tank 5, a hollow rod 18 having a mounting flange 17 at its upper end is inserted into the hollow shaft 13 via a seal member 19.

The hollow shaft portion 13 is connected to a drive source (not shown), the hollow rod 18 is fixed to the base 15, and its through hole 20 is connected to the water pump 6. The mold 2 is inserted into the hollow rod 1 by matching the opening 7 of the holder 3□ with the through hole 20.
The mold 2 is removably erected on the mounting flange 17 of the mold 8, so that the mold 2 is immovably disposed within the tank 5, and the tank 5 is configured to be rotatable around the axis of the mold 2.

On the outer periphery of the mold 2, a plurality of rectifying plates 21 extending in the axial direction and radial direction of the mold 2 are arranged at equal intervals in the circumferential direction. The upper end of each rectifier plate 21 is an annular mounting plate 22
The cover 23 is fixed to the annular ceiling surface of the cover 23 covering the tank 5 through the caps, and each lower end is disposed near the bottom of the tank 5.

The cover 23 is fixed to the upper surface of the base 15 with a plurality of bolts 24, and therefore each rectifier plate 21 is immovably disposed around the outer periphery of the mold 2.

A plurality of first stirring plates 251 are attached to the inner peripheral surface of the tank 5, and these first stirring plates 25. are arranged at equal intervals in the generatrix direction of the inner peripheral surface of the tank 5, and also arranged at equal intervals in the circumferential direction of the inner peripheral surface. The tank 5 rotates clockwise as shown by the arrow in FIG. 4, and each first stirring plate 25. is inclined such that its lower edge is located on the front side in the tank rotational direction, and its upper edge is located on the rear side in the tank rotational direction.

Each of the first stirring plates 25. A plurality of second stirring plates 25. However, each first stirring plate 25.
It is installed so that it overlaps with the rotation locus of. That is, for each current plate 21, the second stirring temporary 2 at the top and middle position
5□ indicates the first Pi1 stirring plates 25. at the top and middle positions, and at the middle and bottom positions while the tank is rotating. The second stirring plate 2 at the lowest position
5□ is located near the bottom of the tank 5 and below the first stirring plate 251 at the lowest position.

In forming the fiber molded body 1, the tank 5 is rotated clockwise in FIG. 4, and the water pump 6 is operated to apply suction into the mold 2.

As a result, in the vicinity of the inner peripheral surface of the tank 5, each of the first and second
Due to the inclination of the stirring plates 25+ and 25i, the molding material is stirred so as to be scraped up, and this stirring action causes the flow of the molding material to become turbulent.

This prevents the molding material from stagnating at the bottom of the tank 5 and allows sufficient stirring.

When the flow of the molding material collides with each rectifier plate 21, the flow velocity is weakened, and also because of the suction effect inside the mold 2, the mold 2 moves as shown by the arrow in FIG.
The flow becomes laminar toward the outer circumferential surface of the As a result, mold 2
The adhesion of the molding material to the molding material is improved, and the molding material that has adhered to the molding material is hardly removed by the flow. Therefore, the production efficiency of the fiber molded body 1 is improved, and the fiber molded body 1 having a uniform thickness can be obtained.

Next, an example of the fiber molded body 1 will be explained.

(a) Preparation of aqueous solution of molding material As reinforcing fibers, carbon fibers with an average diameter of 18 μm and an average length of 0.8 mm are used.
4μm, average length 100-200μm alumina fiber 0
．． 22 to 0.40% by weight, 4 to 6% by weight of silica sol or alumina sol as an inorganic binder, 0.2% by weight of antifoaming agent and surfactant, and 93.4 to 9% of water.
5.4% by weight (321). The calculated fiber concentration in the tank 5 of the molding material thus obtained is 4.2 g/kg.

(bl Dimensions of mold 2 The upper outer diameter is 78 mm, the lower outer diameter is 74 mm, and the thickness is 5 mm.

Using the aqueous solution of the molding material and the mold 2, two types of fiber molded bodies 1 are molded by the apparatus 4 under the conditions shown in Table I.

Table I The fiber adhesion rate is More demanded.

With the conventional device, the rotation speed of the stirring blade was increased to 300° and 520r.
pm, and with the amount of filtrated water and fiber concentration approximately the same as above, two types of fiber molded bodies were molded, and their fiber adhesion rates were determined.
Orpm, it was 94.3%, and at a rotational speed of 52 Orpm, it was 91.8%, so it is clear that the fiber molded article obtained by the apparatus of the present invention is superior in terms of fiber adhesion rate.

Table ■ is under the conditions of Table I above (however, the tank rotation speed is 40
3 shows the variation in fiber concentration around the outer periphery of the mold 2 surrounded by each rectifying plate 21 when the molding operation is performed at a speed of 100 rpm.

Table ■ As is clear from Table ■, the difference between the part with the highest fiber concentration and the part with the lowest fiber concentration is 0.02 g/kg, and therefore the fiber distribution on the outer periphery of the mold 2 is approximately uniform throughout. As a result, the thickness of the fiber molded body 1 can be made uniform.

It has been found that in the case of the conventional device, the difference is 0.04 g/kg, which is twice the value mentioned above.

C3 Effects of the Invention According to the present invention, the molding material is sufficiently stirred by the rotation of the tank, the first and second stirring plates of specific configurations, and the respective rectifying plates, and is efficiently and uniformly applied to the outer circumferential surface of the mold. As a result, the production efficiency of the fiber molded body can be improved and the thickness of the fiber molded body can be made uniform.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a fiber molded product, Fig. 2 is an explanatory diagram of the manufacturing process of the fiber molded product, Fig. 3 is a vertical cross-sectional front view of an embodiment of the device of the present invention, and Fig. 4 is a diagram of Fig. 3 N-mV. Line sectional view, Figure 5 is the first
FIG. 3 is a perspective view showing the relationship between a second stirring plate and a current plate. L... Aqueous solution of molding material, 2... Molding mold, 5... Tank, 6... Lifting pump as suction mechanism, 21... Straightening plate, 25t, 25g
...First. No. 2 stirring plate

Claims (1)

[Claims] A tank containing an aqueous solution of a molding material containing reinforcing fibers, an air-permeable cylindrical mold with both end openings sealed and standing upright in the tank, and a suction action applied to the inside of the mold to agitate the molding material. In the molding device for a reinforcing cylindrical fiber molded body, the molding device is provided with a suction mechanism for adhering the molding material in a state to the outer circumferential surface of the mold, the mold is immovably disposed in the tank, and the tank is configured to be rotatable around the axis of the mold, a plurality of rectifying plates extending in the axial direction and radial direction of the mold are immovably disposed around the outer periphery of the mold, and the inner circumferential generatrix of the tank A plurality of first stirring plates arranged at intervals in the direction and circumferential direction are arranged so that the lower edge of each first stirring plate is located on the front side in the tank rotation direction, and the upper edge is located on the rear side in the tank rotation direction. A plurality of second stirring plates are provided on the inner circumferential surface of the tank with an inclination of A molding device for a reinforcing cylindrical fiber molded body, characterized in that it is provided on a current plate.