JPH0628243Y2 - Ceramic extrusion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a ceramic extrusion molding apparatus suitable for extrusion molding of ceramic materials, particularly extrusion molding of ceramic honeycomb structures.

(Prior Art) Conventionally, in extrusion molding of a ceramic material, as shown in FIG. 4, a columnar ceramic molding material is carried into a material cylinder 3 of an extrusion molding machine 1 from a vacuum clay kneader, and then, It has been performed that the hydraulic plunger 8 is operated to move the piston 4 and the ram head 5 pushes the ceramic forming clay in the two directions of the die.

Immediately before the extrusion of a certain ceramic forming clay batch was completed, the next ceramic forming clay batch was carried into the material cylinder 3 and the extrusion operation was continued in the same manner.

A ceramic molded body or a fired body of the molded body obtained by such an extrusion molding apparatus is a die corresponding to the partition walls of the honeycomb structure, particularly when a ceramic honeycomb structure is molded by a ceramic molding clay batch. Since the forming groove of was very small, the influence between the kneaded clay batches was great.

That is, as shown in FIG. 5, the first formed kneaded clay batch 11 and the next formed kneaded clay batch 12 are not mixed in the extrusion direction, and a defect is likely to occur at the batch boundary surface 13. There was a problem.

In order to reduce such an influence between the kneaded clay batches, as disclosed in U.S. Pat. No. 3,888,963, a kneaded clay flow homogenizer (homogenizer) is provided immediately before the die.
An extrusion molding machine provided with a screen is known. That is, immediately before the upstream side of the mouthpiece 2 in FIG. 4, a plurality of penetrations are made in the kneaded material flow direction as shown in the plan view and the AA ′ sectional view of FIGS. 6 (A) and 6 (B). A kneaded clay flow homogenizer (homogenizer) 16 having holes 15 is installed,
The kneaded clay batch is crushed to obtain a good honeycomb structure.

(Problems to be Solved by the Invention) However, the above-mentioned US Patent Specification No. 3,888,96
In the extruder disclosed in No. 3, since the seam between the ceramic forming clay batches is crushed, it has the effect of reducing the variation between batches, but the non-uniformity at the boundary between batches still remains. . In addition, since the cross-sectional area of the material cylinder and the mouthpiece part of the kneaded clay is usually different, flow velocity distribution of the kneaded material occurs, and the influence of unevenness on the boundary surface between batches reaches 10 to 20 extruded products. There was also a problem.

An object of the present invention is to solve the above-mentioned problems and to provide a ceramic extrusion molding apparatus capable of obtaining a molded product having good properties without any influence between kneaded clay batches.

(Means for Solving the Problems) A ceramic extrusion molding apparatus of the present invention includes a material cylinder, a die for extruding a ceramic structure provided at an end of the material cylinder into a predetermined shape, and a material cylinder. Provided on the upstream side of the die, at least with a kneaded material flow homogenizing means consisting of a large number of through-holes for crushing the kneaded material, in the ceramic extrusion molding apparatus for charging the ceramic kneaded material batch into the material cylinder, It is characterized in that the flow resistance of the kneaded clay flow homogenizing means is made smaller toward the outer peripheral portion.

(Operation) In the above-mentioned configuration, since the opening ratio of the large number of through holes of the kneaded material flow homogenizing means is increased toward the outer peripheral portion, resistance is applied to the central portion, which delays the kneaded material in the central portion. It is offset by the flow velocity distribution generated by the squeezing just before the base. As a result, the boundary surface between the ceramic molded kneaded clay batches to be extruded becomes close to the surface perpendicular to the extrusion direction, so that the defect occurrence rate between the ceramic molded kneaded clay batches can be reduced.

(Embodiment) FIGS. 1 (A) and 1 (B) are a plan view and an AA 'sectional view showing an example of a kneaded clay flow homogenizing means in the present invention. In the kneaded clay flow homogenizing means 17 of the present embodiment, the through holes 15 in the kneaded clay flow direction are arranged substantially concentrically, and the opening ratio of the through holes 15 is gradually increased from the central portion toward the outer peripheral portion. That is, an example in which the hole diameter of the through hole 15 is increased toward the outer peripheral portion is shown.

In this example, the conventional clay flow homogenizing means (homogenizer)
In the same way as the kneading of the kneaded clay can be achieved, the resistance to the central part due to the change in the opening ratio between the central part and the outer peripheral part delays the flow of the kneaded material in the central part, and The flow velocity distribution generated by the squeezing can be canceled out.

That is, as shown in FIG. 2 in which the tip of the material cylinder of the molding machine of the present invention is enlarged, the kneaded material that has passed through the mesh-shaped screen 18 and the kneaded material flow homogenizing means 17 is
As the length of the arrow in the figure is displayed corresponding to the flow velocity, the kneaded clay flow becomes faster in the outer peripheral portion than in the central portion.
Further, since the kneading flow just before passing through the squeezing part 19 and reaching the mouthpiece 2 becomes faster in the central part as compared with the outer peripheral part, the kneading is made before the kneading of the kneading flow homogenizing means 17. It can be supplied to the base 2 in substantially the same state. The change in the opening ratio of the hole diameter of the through hole 15 of the kneaded clay flow homogenizing means 17,
It is necessary to determine in consideration of the squeezing state of the squeezing portion 19.

FIG. 3 shows a cross section parallel to the extrusion direction of the batch seam portion of the molded product extruded by the extrusion molding machine of the present invention described above. That is, a pigment was applied to the rear end or the front end of the ceramic kneaded clay batch to examine the boundary surface. As a result, as shown in FIG. 3, the boundary surface 23 between the ceramic kneaded clay batch 21 and the second ceramic batch 22 was closer to the vertical direction in the extrusion direction as compared with FIG. It was found that the soil flow was uniform.

The device of the present invention can be modified in many ways. For example, in this embodiment, an example in which the hole diameter of the through hole is gradually increased toward the outer circumference has been shown, but the homogenizing means may be gradually thinned toward the outer circumference. The diameter of the through holes may be the same, and the number of holes may be gradually increased toward the outer circumference.

(Effect of the Invention) As is clear from the above description, according to the ceramic extrusion molding apparatus of the present invention, by using the kneaded material flow homogenizing means having a smaller flow resistance toward the outer peripheral portion, the ceramic molding material is formed. The interface between the batches can be made nearly vertical to the extrusion direction, and the defect rate between the ceramic forming clay batches can be reduced.

[Brief description of drawings]

1 (A) and 1 (B) are a plan view showing an example of the kneaded clay flow homogenizing means in the present invention and a sectional view taken along the line AA ', and FIG. 2 is an enlarged view of the die part of the forming machine of the present invention. Fig. 3 is a sectional view of an extruded body of a ceramic kneaded clay batch produced by the extruder of the present invention, Fig. 4 is a front view of a conventional ceramic extruder, and Fig. 5 is a conventional extruder. 6A and 6B are a plan view and an AA ′ cross-sectional view showing an example of a conventional clay flow homogenizing means. 15 …… Through hole, 17 …… Pour flow homogenization means 18 …… Screen, 19 …… Squeezing part 21 …… Ceramic clay batch 22 …… Second ceramic clay batch 23 …… Boundary surface

Claims (1)

[Scope of utility model registration request] 1. A material cylinder, a die for extruding a ceramic structure provided at an end of the material cylinder into a predetermined shape, and a kneaded material provided in an upstream side of the die in the material cylinder. At least a kneading flow homogenizing means consisting of a large number of through holes for, in the ceramic extrusion molding device to put the ceramic kneading batch into the material cylinder, the flow resistance of the kneading flow homogenizing means to the outer peripheral part Ceramic extrusion molding device characterized by being made smaller.