JP2828730B2 - Shelf and molding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to, for example, a refractory shelf used for firing ceramic products, and a shelf used for manufacturing the shelf. To a molding apparatus.

2. Description of the Related Art For firing ceramic products such as tiles and tiles, for example, an article to be fired is placed on a shelf board arranged in a firing furnace. As shown in FIG. 10, such a shelf 1 is formed of a refractory into a rectangular plate shape, and is provided with slit-shaped grooves 2 extending inward from four edges thereof. It is known that the provision of the groove 2 significantly improves spalling resistance as compared with the case without the groove 2.

The length of the groove 2 is generally determined by the groove 2
It is said that the length of the edge extending in the same direction is preferably in the range of 15 to 37%, but if it is too long, the mechanical strength of the shelf 1 will be weakened. Therefore, in consideration of the balance between the spalling resistance and the mechanical strength of the shelf 1, experimentally or empirically, for example, the length of the shelf 1 is determined according to the size or the application. . In this case, as the shelf 1 becomes larger, the temperature difference between the central portion and the peripheral portion of the shelf 1 during use becomes larger. It is also desirable to increase.

By the way, such a shelf board is manufactured by drying and firing a compact formed by compressing and molding a material powder. In order to improve the productivity, the groove 2 is generally formed at a molding stage. It is formed.

(Problems to be Solved by the Invention) However, in the case where the grooves 2 are formed as described above, a load or heat received on both sides of the grooves 2 during a drying or firing step during manufacturing or during use. Due to factors such as differences in dynamic strain
As shown in the figure, both sides of the groove 2 at the outer edge of the shelf 1 are vertically displaced, and a step A may occur. If such a step A occurs, there is a problem that the placed article to be fired is deformed following the step A during heating. In particular, in the case of large shelves used for firing large tiles and the like recently provided, the size of the step A is also 0.5 m due to the fact that the length dimension (ratio) of the groove 2 becomes large.
m, which may be large, and improvement is demanded.

Further, in a conventional molding apparatus for manufacturing such a molded body of a shelf board, as shown in FIG. 12, a thin plate 4 for forming a groove portion is fixed to a bottomed mold 3 and this mold 3 A predetermined amount of material powder is accommodated in the inside, and the material powder is compressed by a movable mold (not shown). However, in this case, the thin plate 4 may be deformed or broken by receiving a large force at the time of compression, and the thin plate 4 may interfere with the release of the molded body from the mold frame 3 by having the thin plate 4. There was also a problem that the properties became worse.

The present invention has been made in view of the above circumstances, and one object of the present invention is to provide a shelf plate having good spalling resistance and capable of preventing occurrence of a step at an outer edge portion.

Another object of the present invention is to provide a shelf plate forming apparatus that is suitable for forming the shelf plate and that can reduce the breakage of the groove forming thin plate and improve the releasability of the formed body. is there.

[Means for Solving the Problems] The shelf board of the present invention is formed in a plate shape by a refractory material, and is provided with a groove extending inward from an outer edge portion. A connecting portion for connecting both sides of the groove portion is formed at an end portion on the outer edge side, and the connecting portion is connected at the time of molding and firing, and has a thickness dimension such that cracks occur with actual use. Is characterized by the configuration having

In this case, the groove is formed in a bottomed state,
The connecting portion may be formed to be thicker in the thickness direction than the bottom portion of the groove.

The shelf plate forming apparatus of the present invention is a device for forming the above-mentioned shelf plate, wherein a mold forming an outer shape of a peripheral portion of the shelf, an upper mold for closing an upper surface of the mold, and a mold. And a lower mold that is vertically movably provided in the upper mold and compresses the material between the upper mold and the lower mold, wherein the lower mold is provided with a slit that extends in a direction away from the outer edge from slightly inside the outer edge. In addition, a feature is that a groove forming plate that penetrates the slit and protrudes into a cavity between the upper mold and the lower mold is provided so as to be relatively movable with respect to the lower mold.

(Operation) According to the shelf board of the present invention, since the ends on the outer edge side of the grooves are connected by the connecting portions, the drying or heating is performed as compared with the case where both sides are separated by the grooves. The strength against a force that tends to form a step that occurs sometimes becomes large. As a result, errors during molding and firing are prevented. Then, due to the thermal expansion and thermal contraction of the shelf plate due to heating and cooling during use, pulling and compressing force acts on both sides of the groove in the groove width direction. Cracks are easily formed in the direction of extension. Due to the generation of the cracks, the grooves exhibit the same effect as those opened at the outer edge of the shelf, and can absorb the internal stress caused by thermal expansion and thermal contraction, thereby preventing the occurrence of spalling. .

Further, the groove portion may have a bottomed shape without penetrating in the thickness direction of the shelf board, and similarly, occurrence of a step due to the connecting portion is prevented. In this case, the connecting portion is made thicker than the bottom portion of the groove, in other words, if the bottom portion of the groove is made thinner than the connecting portion, the bottom portion of the groove can be easily attached to the bottom portion in actual use. Cracks are generated to perform the same function as the groove penetrating in the thickness direction, and sufficient spalling resistance can also be obtained.

According to the shelf plate forming apparatus of the present invention, the groove having the above-mentioned connection portion is formed in the formed body by the groove forming plate which penetrates the slit of the lower die and protrudes into the cavity. be able to. In this case, since the groove forming plate is relatively movable with respect to the lower mold, it can move in the direction in which it escapes from the cavity, so that it does not need to be subjected to a force that causes breakage during compression molding of the molded body, and When the molded product is released from the mold, the groove forming plate can be relatively moved from the lower mold so that the releasability can be improved.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

1 to 4 show a shelf board 11 according to the present embodiment. The shelf plate 11 is formed in a rectangular plate shape from a refractory material such as silicon carbide as described later, and in this case, six groove portions 12 are formed. The shelf board 11 is used, for example, for firing large tiles, and has a width and a length of 48, respectively.
It has a large size of 0mm, 690mm and a thickness of 18mm.

In this case, the groove portion 12 is formed in a slit shape having a width dimension of about 2.3 mm which is vertically opened in this case, and is formed so as to extend substantially inward from the four side edges of the shelf board 11 inward. . In this case, one groove portion 12 is formed on the short side portion of the shelf plate 11 and two groove portions are formed on the long side portion thereof, and they are provided symmetrically so as not to be aligned with each other. I have. The length of the groove 12 is, for example, 28% longer than the length of the edge extending in the same direction as the groove 12.

The outer edge 12a of the groove 12 is located slightly inside the edge of the shelf 11 as shown in FIGS. The distance between the edge 12a and the edge varies depending on the length of the groove 12 and the like.
It is preferably 3 mm, and in this embodiment, it is 5 mm. As a result, the edges of the shelf board 11 are connected without being divided, and thus, a connecting portion 13 that connects both sides of the groove 12 is formed. The end 12b of the groove 12 inside the shelf 11 is
As shown in FIG. 2, it is formed in a circular shape.

Here, a method of manufacturing the shelf board 11 formed as described above will be described with reference to FIGS.

Shelf plate 11 is manufactured by compression-molding a silicon carbide material powder into a plate to form a compact, drying the compact, and firing it. Of these, in the molding step, a groove corresponding to the groove 12 is formed in the molded body. In this molding, according to the present embodiment, as shown in FIG. 5 and FIG. A molding device 14 is used.

This molding device 14 is configured as follows. That is,
Although not shown in detail, a rectangular frame that forms the outer shape of the peripheral portion of the shelf 11 is provided above the base of the molding apparatus. A lower mold 16 that is vertically moved by the ram 15 is inserted into the mold to form a bottom of the mold. On the other hand, the upper holding plate 17
Is set detachably. These molds, lower mold 16,
The upper holding plate 17 forms a cavity. Then, in the lower mold 16, at a position corresponding to the groove 12 of the shelf board 11,
A slit 16a that opens vertically is formed. Therefore, the slit 16a extends inward at right angles from a position slightly inside the edge of the lower die 16. And
The groove forming plate 18 is provided so as to be vertically movable relative to the lower die 16 through the slit 16a. The groove forming plate 18 has a cross-sectional shape corresponding to the groove portion 12 and has a vertically long thin plate shape. Two bolts 20 project from the lower surface of the support base 19, and these bolts 20 pass through a receiving rod 21 provided on the base, and are screwed to a nut 22 on the lower surface of the receiving rod 21. doing. A spring 23 is inserted into the bolt 20, whereby the groove forming plate 18 is urged upward so as to be movable downward.

In order to form a molded body by the molding apparatus 14 having the above configuration, first, the lower mold 16 is set at a predetermined position with the upper holding plate 17 removed, and the material powder is placed in a mold by a feeder (not shown). Storing a fixed amount. Next, the upper holding plate 17 is set so as to cover the upper surface of the mold. Thus, the groove forming plate 18
The upper edge portion is brought into contact with the upper holding plate 17. By raising the lower mold 16 in this state, as shown in FIG. 5, the material powder 24 in the cavity is compression molded into a plate shape with the groove forming plate 18 embedded therein. At this time, the groove forming plate 18 can slide in the slit 16a and move relatively downward with respect to the lower die 16, so that no force that causes deformation or breakage acts on the groove forming plate 18. After that, remove the upper presser plate 17,
Lower die 16 is further raised to the top of the formwork. Then, along with this, the groove forming plate 18 is relatively moved so as to sink from the lower mold 16, and the molded body can be easily removed from the lower mold 16 without the groove forming plate 18 being in the way.

Thus, the shelf board 11 provided with the above-described groove portion 12 and connection portion 13
Then, the molded body is dried and then fired to form the shelf board 11.

Thus, in the case where the groove is formed in the molded body during molding, the molded body (shelf plate 11) is subjected to a load or thermal strain applied to the molded body in the drying or firing step. In some cases, a force may act in a direction in which a step is formed on both sides of the groove portion 12 at the outer edge portion. However, in the present embodiment, since the connecting portion (connecting portion 13) for connecting both sides of the groove is formed at the outer edge of the molded body, compared to the case where both sides of the groove are separated, it can be dried or dried. The strength against a force for forming a step due to distortion during heating is large. As a result, it is possible to prevent a step from occurring in the formed shelf board 11.

According to the shelf board 11 of the present embodiment, during use at a high temperature, the force in the direction of forming a step on both sides of the groove 12 due to factors such as its own weight and the weight of the mounted object, or thermal strain. However, the presence of the connecting portion 13 also increases the strength against the force for forming the step, so that the occurrence of the step can be prevented. In addition, due to thermal expansion and contraction of the shelf plate 11 due to heating and cooling during use, the groove 12
Pulling and compressing force acts in the groove width direction.
A crack 25 (see FIG. 3) can easily enter the connecting portion 13 in the direction in which the groove 12 extends in the outer edge direction. Due to the generation of the cracks 25, the grooves 12 exhibit the same function as those opened at the outer edge of the shelf board 11, and can absorb internal stress caused by thermal expansion and thermal contraction, thereby preventing spalling. Is what you can do.

By the way, once the crack 25 is generated, the connection by the connecting portion 13 is disconnected, and the effect of preventing the occurrence of the step is considered to be lost at that time. However, for the following reasons, the effect of preventing the occurrence of a step is maintained to some extent. That is,
The material powder 24 constituting the shelf board 11 is mixed with various particle diameters, for example, the coarse powder 2 having a maximum particle diameter of 3 to 5 mm.
6 are included. For this reason, as shown in FIG. 3, the cracks 25 do not extend straight in the vertical direction but extend in a zigzag manner along the outer shape of the coarse grains 26. Thus, the surfaces on both sides sandwiching the crack 25 are in a state of meshing with each other, so to say, can be prevented from shifting in the vertical direction. Moreover, the larger the coarse particles 26 are,
Because its presence increases the depth of engagement,
Even if the crack 25 part is expanded to some extent, it is possible to prevent the vertical displacement and the occurrence of the step.

As described above, according to the shelf board 11 of the present embodiment, the spalling resistance can be improved by the groove portion 12 as in the conventional case, and the occurrence of a step in the related art is inevitable. Even if the shelf 11 is shaped and the length (ratio) of the groove 12 is large, the connecting portion 13 can prevent a step at the outer edge. Then, the occurrence of the step can be prevented for a long time not only at the time of manufacturing but also at the time of use as a shelf board, and the service life can be extended.

Further, according to the molding apparatus 14 of the present embodiment, it is possible to form the groove portion in a state where the above-described connecting portion is secured in the molded body, and furthermore, the groove forming plate 18 may be damaged as compared with the conventional one. And the mold release property of the molded article can be improved.

In the above-described embodiment, the connecting portion 13 is formed to have a thickness equal to the thickness of the shelf board 11. However, for example, as shown in FIG. It may be formed so as to connect only a part, in short, the connecting portion is
It should be provided so that it is connected at the time of molding and firing, and has such a thickness that cracks occur during actual use.

FIG. 8 and FIG. 9 show another embodiment of the present invention which is different from the above embodiment. The difference from the above embodiment is that instead of the groove 12 which is opened up and down, the bottomed groove 28, 29. In this case, the connecting portions 30 and 31 are made thicker in the thickness direction than the bottom components of the grooves 28 and 29, and the intended purpose can be achieved also by such a configuration.

In addition, the present invention is not limited to the embodiment described above and shown in the drawings. For example, the groove may be formed so as to extend obliquely with respect to the edge. Various changes can be made without departing from the gist, such as application to various things.

[Effects of the Invention] As is clear from the above description, the present invention has the following excellent effects.

That is, according to the shelf board of the present invention, the spalling resistance is good, and the occurrence of a step at the outer edge can be prevented.

According to the shelf plate forming apparatus of the present invention, the shelf plate is suitable for forming, and the thin plate for forming the groove is less likely to be damaged, and the mold releasability of the formed body can be improved.

[Brief description of the drawings]

1 to 6 show an embodiment of the present invention. FIG. 1 is a plan view of the entire shelf, FIG. 2 is an enlarged plan view of a groove portion, and FIG. 3 is a perspective view of a connecting portion. Fig. 4 is a longitudinal sectional view of a groove portion, Fig. 5 is a longitudinal sectional view of a main part of the molding apparatus, and Fig. 6 is a perspective view of a main part of the molding apparatus. 7 to 9 are views corresponding to FIG. 4, showing other different embodiments of the present invention. 10 to 12 show a conventional example, FIG. 10 is a plan view of a shelf, FIG. 11 is a front view showing a state where a step is formed on both sides of a groove, and FIG. It is a perspective view of the principal part of an apparatus. In the drawing, 11 is a shelf board, 12, 28, 29 are grooves, 13, 27, 30, 31 are connecting parts, 14 is a molding device, 16 is a lower mold, 16a is a slit, and 17 is an upper holding plate (upper mold). , 18 indicate a groove forming plate, 24 indicates a material powder, and 25 indicates a crack.

Continuation of the front page (56) References JP-A-62-21507 (JP, A) JP-A-53-142548 (JP, U) JP-A-53-142547 (JP, U) JP-B 1-38646 (JP) , B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) F27D 3/12 B28B 3/02 C04B 35/64

Claims (3)

(57) [Claims] 1. A groove formed in a plate shape from a refractory and extending inward from an outer edge portion,
A connecting portion for connecting both sides of the groove portion is formed at an end portion of the groove portion on the outer edge side, and the connecting portion is connected at the time of molding and firing, so that cracks are generated with actual use. A shelf board having a thickness dimension of: 2. The groove is formed in a bottomed state.
The shelf according to claim 1, wherein the connecting portion is formed to be thicker in the thickness direction than the bottom portion of the groove. 3. A shelf for molding a shelf according to claim 1 or 2, wherein a mold forming an outer shape of a peripheral edge of the shelf is provided;
An upper mold for closing the upper surface of the mold, and a lower mold for compressing and molding a material between the upper mold and the upper mold, the lower mold being provided in the mold so as to be vertically movable. A slit extending from a slightly inside of the outer edge portion in a direction away from the outer edge portion is provided, and a groove forming plate penetrating this slit and projecting into a cavity between the upper die and the lower die is formed with respect to the lower die. A shelf plate forming apparatus provided in a relatively movable state.