JPH02293103A - Honeycomb molding mouthpiece - Google Patents

Abstract

PURPOSE:To prevent a pin from falling off by improving strength, by a method wherein an area of an end surface of an inlet side of the outermost circumferential pin forming the outermost circumferential cell of a honeycomb molding mouthpiece is made larger than an area of a downstream end surface and a sectional layer at the root of a forming pin of the outermost circumferential cell is increased. CONSTITUTION:A honeycomb molding mouthpiece is constituted of a die 3 and an outer frame 4. An area of end surface of an inlet side of a basic pin 5 surrounded by a discharge channel for formation of a cell and an area of an end surface of a downstream side of the same are equalized to each other in the said mouthpiece. The outermost circumferential pin 6 possesses a downstream side end surface 11, the inlet side end surface 7 having a larger area than that of the said downstream side end surface and a pin rest 8 facing toward the inlet side by starting from an intermediate part of a pin length. Since an inlet side sectional area of body of the outermost circumferential pin is larger than an outlet side sectional area of the same, is attained a stabilized state of fitting.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a die for extrusion molding a ceramic honeycomb, and more particularly, to a die having a structure suitable for forming cells near the outer periphery of a formed honeycomb body.

[Conventional technology]

Ceramic honeycombs generally have a large surface area per unit volume, low pressure loss, and excellent heat dissipation, so they are used as carriers or support materials for automobile exhaust gas purification catalysts, combustion catalysts, etc. The method for forming such a ceramic honeycomb is as follows:
Examples include extrusion method, corrugation method, paper dipping method, etc. Among these, the extrusion method is a method in which ceramic clay is pressurized with an extruder and extruded from a die to form it. (1) It can be processed continuously, so it has excellent productivity. (2) It can be used as desired depending on the shape of the die. (3) The resulting honeycomb has higher strength than those obtained by the corrugating method or paper dipping method.
Due to these features, it is currently the mainstream method of honeycomb forming.

The structure of the die used for honeycomb extrusion molding is, for example,
As described in Japanese Unexamined Patent Publication No. 47-42386, there is a porous section located on the upstream side for dividing and supplying clay, and a lattice formation extending downstream thereof and continuing in the stacking direction. It has a slit section for.

FIG. 4 is a partial plan view of such a conventional honeycomb forming die, and FIG. 5 is a partial sectional view of the die shown in FIG.

In FIGS. 4 and 5, a mold 3 is fitted into an outer frame 4, and the mold 3 has a porous portion l for dividing and supplying clay and a slit portion located downstream thereof to form a lattice. It consists of 2.

The slit portion 2 is formed by a rectangular basic pin 5 and a deformed outermost pin 6 arranged on the clay outlet side of the mold 3.

The arrow in FIG. 5 indicates the direction of supply of clay.

The shape of the outermost pin 6 located at the outermost periphery of the die to form the outermost cell of the honeycomb is determined by the shape of the cell and the outer shape of the honeycomb. For example, if the cells are rectangular and the honeycomb outer shape is circular, The cross-sectional shape of the outermost pin is triangular or trapezoidal.

When extrusion molding a honeycomb using such a die, external force may cause the pins in the outermost cell portion to come loose and fall off or break. This phenomenon is particularly noticeable when the outer shape of the honeycomb is curved, or when the shape of the senole and the outer shape of the honeycomb are geometrically different. That is, the cross-sectional shape of the outermost pin 6 located at the outermost part of the die for forming the outermost cell of the honeycomb is a unique shape such as a triangle, and the cross-sectional shape is perpendicular to the clay flow formed by the outermost pin 6. The cross-sectional area of is smaller than the cross-sectional area formed by the basic pin 5.

7 is a perspective view showing the structure of the outermost pin of the base of FIG. 4. FIG. In FIG. 7, the cross-sectional area of the root portion 7 of the mold 3 supporting the outermost pin 6 is extremely small compared to the cross-sectional area of the root portion 7 of the basic pin 5 shown in FIG. I understand that. Moreover, since the length of the pin is the same for the basic pin 5 and the outermost pin 6, when an external force is applied to the outermost pin 6, large bending stress or bowing stress is generated at the root portion 7. It becomes easily damaged and may fall off during extrusion molding. Furthermore, the flow resistance of the flow path where the pin has come out is smaller than the resistance of other parts, making the flow velocity distribution uneven over the entire surface of the nozzle.

As a result, the molded body may bend and flow out, or in extreme cases,
Clay may flow out in the form of noodles from the area where the pin came out. Such a phenomenon is more likely to occur in a die with a narrow slit width and a large flow resistance. As a result, the product value of the honeycomb is significantly reduced.

[Problem to be solved by the invention]

The above conventional technology does not take into consideration the strength of the outermost cell forming pin of the honeycomb forming die, and the outermost pin falls off during extrusion molding, resulting in uneven flow rate of the molded product. There was a problem that localized abnormal eruptions of clay occurred.

An object of the present invention is to provide a honeycomb forming die having a structure that prevents the outermost pin of honeycomb metal from falling off and forms a sound honeycomb. [Means for Solving the Problems] The above object consists of an outer frame and a mold, and the mold has a porous part located on the inlet side of the clay to supply the clay in parts and a downstream part of the porous part. A slit portion for forming a honeycomb, and a plurality of basic pins for forming honeycomb cells and a plurality of outermost pins for forming the outermost cells of the honeycomb are attached to the slit portion. This is achieved by a honeycomb forming die characterized in that the area of the end face on the inlet side of the mounting portion of the plurality of outermost circumferential pins is larger than the area of the end face on the downstream side.

[Effect]

In the present invention, the area of the inlet side end surface of the outermost peripheral pin 6 forming the outermost peripheral cell of the honeycomb is made larger than the area of the downstream end surface, and the porous portion is arranged to the outside of the groove for forming the outer circumferential ring of the honeycomb. For example, if the support cross-sectional area of the outermost pin of the cap at the root part is made equal to the support cross-sectional area of the basic pin, the strength of the root part of the outermost pin for forming the outermost cell will depend on the shape of the downstream end surface. Regardless, the strength of the base pin can be made equal to the strength of the base pin. Moreover, the clay that has passed through the supply channel located outside the slit flows toward the slit surrounded by the outermost pin and the outer frame, thereby forming the outermost circumferential ring. Due to these effects,
It is possible to prevent the outermost pin 6 from falling off and form a honeycomb with a sound shape.

Hereinafter, the present invention will be explained in detail with reference to Examples.

〔Example〕

FIG. 1 is a partial plan view of the honeycomb forming die of the present invention;
FIG. 2 is a partial sectional view of the base shown in FIG. 1.

In Figures 1 and 2, the honeycomb forming die is
It is composed of a mold 3 and an outer frame 4.

The mold 3 includes a porous part 1 for supplying clay in divided parts and a slit part 2 forming a lattice connected in the horizontal direction. A plurality of outermost pins 6 having a shape of oddly shaped cells are attached along the pins 5 and the parallel grooves 10 for forming the honeycomb outer circumference. The outer frame 4 forms an outermost cell-forming parallel: a10 between the outer frame 4 and the mold 3, and fixes the mold 3 to the extruder outlet. The clay sent from an extruder (not shown) is supplied to the mold 4 as shown by the arrow, passes through the porous section 1, and then passes through the slit section 2 to be discharged as a continuous body having a honeycomb structure. be done.

In the honeycomb forming die of the present invention shown in FIGS. 1 and 2, the cell shape is square and the honeycomb outer shape is circular. In this die, the basic pin 5 (the part surrounded by the discharge flow path) for forming cells is a square prism as in the structure of the conventional honeycomb forming die.
The area of the inlet side end face and the area of the downstream end face are equal. On the other hand, the outermost pin 6 has a downstream end surface l1, an inlet end surface 7 having a larger area than the downstream end surface, and an intermediate point between the pin lengths, as shown in FIG. It has a pin stand 8 starting from the section and facing towards the entrance side. As is clear from the figure, the cross-sectional area of the outermost pin on the molding side is larger than the cross-sectional area on the exit side, resulting in a stable attachment state. Although FIG. 3 shows a case where the tip 11 has a triangular shape, the tip 11 may have an irregular shape such as a square. In any case, the cross-sectional shape of the root and the supporting cross-sectional area 7 of the pin are the same as those of the basic pin 5 shown in FIG. 6, and therefore it is possible to provide the same support strength as the basic pin 5. can. Therefore, the problem of the outermost pin falling out, which occurred in the conventional honeycomb forming die shown in Fig. 5, is fundamentally solved. Further, the outermost circumferential tube is formed by a channel 10 surrounded by the outermost circumferential pin 6 and the outer frame 4. That is, the clay that has exited the supply channel is sent from the side surface of the outermost pin 6, through the inclined surface of the outermost pin stand 8, to the parallel groove 10 surrounded by the pin tip l1 and the outer frame 4, and is then honeycomb-formed. It is pushed out around the outside of the body. Note that even if there is no gap formed between the sloped surface of the pin stand 8 and the sloped surface of the outer frame 4 and the surfaces of the outer peripheral plate are in contact with each other,
Molding can be performed as long as the parallel grooves 10 are provided. Appropriate molding conditions for the outer slit and cell are the width of the outer slit,
This is determined by the width of the internal slit, the size of the cells, the properties of the clay, etc., but it is sufficient that the above conditions are adjusted so that the flow velocity distribution in the inside of the molded body and the outermost part of the molded body are approximately equal. In the present invention, when the cell shape is triangular and the outer shape is circular, oval, or rectangular, the cell shape is polygonal and the outer shape is circular,
It can also be applied to oval or rectangular shapes. (Effects of the Invention) In the honeycomb forming die of the present invention, since the area of the inlet side end surface of the outermost pin forming the outermost cell is larger than the area of the downstream end surface, the supporting cross-sectional area at the root of the pin for forming the outermost cell is This increases the strength and prevents pins from falling out.In addition, the clay that has passed through the supply flow path located outside of the outermost pin flows toward the slit surrounded by the outermost pin and the outer frame. As a result, the outermost circumferential pin can be easily formed.Therefore, unlike conventional methods, local ejection of clay due to falling of the outermost circumferential pin and bending of the molded body and outflow are not caused. , it is possible to improve product quality and yield.

[Brief explanation of drawings]

FIG. 1 is a partial plan view of the honeycomb forming die of the present invention as seen from the downstream side, FIG. 2 is a partial sectional view of the honeycomb forming die of the present invention, and FIG. 3 is a partial plan view of the honeycomb forming die of the present invention. FIG. 4 is a perspective view showing the outermost pin structure of the die; FIG. 4 is a partial plan view of a conventional honeycomb forming die seen from the downstream side; FIG. 5 is a partial sectional view of the conventional honeycomb forming die; The diagram is
FIG. 7 is a perspective view showing the basic pin structure of a conventional honeycomb forming die. FIG. 7 is a perspective view showing the outermost pin structure of a conventional honeycomb forming die. 1... Porous part, 2... Slit part, 3... Mold,
4...Outer frame, 5...Basic pin, 6...Outermost pin, 10...Parallel groove for forming outer circumference. Applicant Babcock Hitachi Co., Ltd. Agent Patent Attorney Takeshi Kawakita 7: Pin support cross section 8: Pin base, 1]: Second downstream end surface of outermost pin

Claims (1)

[Claims] (1) Consisting of an outer frame and a mold, the mold includes a porous part located on the inlet side of the clay to supply the clay in divided parts, and a porous part located downstream of the porous part for forming a honeycomb. A honeycomb forming die comprising a slit portion, and a plurality of basic pins forming cells of the honeycomb and a plurality of outermost pins forming the outermost cells of the honeycomb are attached to the slit portion,
A honeycomb forming die characterized in that the area of the end face on the inlet side of the mounting portion of the plurality of outermost circumferential pins is larger than the area of the end face on the downstream side.