JP2015058591A - Extrusion molding device and method for manufacturing honeycomb molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent shape distortion occurring in a honeycomb molding by controlling the temperature of a tip part provided with a mold of an extrusion molding device.SOLUTION: An extrusion molding device includes a charging port through which a raw material including a silicon carbide powder is supplied, a kneading part which kneads the raw material with a screw, an extrusion molding part which is provided with a tip part arranged with a mold and produces a continuous honeycomb molding, and a conveyance part which cuts the continuous honeycomb molding into a predetermined length. A flowing water pipe for cooling a kneaded product is arranged at the tip part. The flowing water pipe is connected to a flowing water inflow pipe and a flowing water discharge pipe. A flow rate control mechanism for controlling the flow rate of circulating cooling water is arranged in at least one of the flowing water inflow pipe and the flowing water discharge pipe. The conveyance part is provided with at least one height sensor for measuring the height in a direction vertical to the extrusion direction of the honeycomb molding. The flow rate of the cooling water is controlled by the flow rate control mechanism on the basis of the vertical height.

Description

The present invention relates to an extrusion molding apparatus and a method for manufacturing a honeycomb molded body.

In exhaust gas discharged from internal combustion engines such as diesel engines, particulates such as soot (hereinafter also referred to as PM) are included, and in recent years, it has been a problem that this PM is harmful to the environment or the human body. ing. Further, since harmful gas components such as CO, HC or NOx are contained in the exhaust gas, there is a concern about the influence of the harmful gas components on the environment or the human body.

Therefore, cordierite is used as an exhaust gas purification device that collects PM in exhaust gas by being connected to an internal combustion engine and purifies harmful gas components in exhaust gas such as CO, HC or NOx contained in the exhaust gas. Various honeycomb structures having a structure in which a large number of cells are juxtaposed in the longitudinal direction have been proposed.

When manufacturing this type of honeycomb structure, first, a ceramic powder, an organic binder, a solvent such as water, a pore former, a molding aid, etc. are uniformly mixed, and then kneaded to have an optimum viscosity. A kneaded material is prepared. The kneaded product is extruded through a mold to produce a continuous honeycomb formed body in which a large number of through holes are arranged in the longitudinal direction.

Next, the continuous honeycomb formed body is cut into a predetermined length and then dried, and if necessary, plugged with a plugging paste on one end face of the through hole of the honeycomb formed body. Subsequently, after drying the plugged paste for plugging, the honeycomb formed body is degreased and fired, whereby a honeycomb structure made of porous ceramic can be manufactured. Thereafter, if necessary, a plurality of honeycomb structures are bundled through an adhesive, and peripheral processing, peripheral coating, and the like are performed, whereby a honeycomb filter including a plurality of honeycomb structures can be manufactured.

There are a large number of documents relating to the manufacturing method of such a honeycomb structure, and among them, Patent Document 1 describes the formation of a molded body immediately after extrusion in order to prevent occurrence of shape distortion in the extruded honeycomb formed body. A method for extruding a ceramic molded body is disclosed in which the temperature is set to 30 ° C. or lower and the temperature difference between the outer peripheral temperature Tb and the center temperature Ta of the extruded molded body is 1 ° C. ≦ Ta−Tb ≦ 5 ° C. .

Further, in Patent Document 2, in the above-described continuous honeycomb formed body cutting step, a linear member such as a wire is moved up and down while moving at a moving speed synchronized with the moving speed of the continuous honeycomb formed body, thereby forming a continuous honeycomb formed body. A cutting method and a cutting device for cutting perpendicularly to the longitudinal direction of a body are disclosed.

Patent Document 3 discloses an extrusion molding apparatus that suppresses pulsation of extrusion pressure near the die during molding and improves molding quality, and a method of manufacturing a molded body using the extrusion molding apparatus. In order to obtain the above effect, this extrusion molding apparatus has a supply port side screw provided with two rotating blades as a screw on the supply port side and an extrusion port provided with one rotating blade as a screw on the extrusion port side. A side screw is provided, and when the diameter of the outermost periphery of the rotary blade is D and the pitch of the extrusion port side rotary blade in the extrusion direction parallel to the rotation axis is P, P / D is 0.5 to 0.9. The range is set.

Patent Document 4 discloses an extrusion molding machine that can prevent deformation and distortion that occur in a generated shape when manufacturing a honeycomb formed body and can manufacture a large honeycomb filter or a honeycomb filter with a thin cell wall. It is disclosed. In order to obtain such an effect, it is possible to immediately freeze and maintain the generated shape in a fixed shape by introducing the generated shape mainly made of silicon carbide discharged from the extruder into a freezer containing a refrigerant. It is disclosed.

Patent Document 5 discloses an extrusion molding machine capable of producing a molded body that has little wear on a blade portion of a screw, has a long life, and has a very low possibility of occurrence of a defect or the like. In order to obtain such an effect, the space in which the wet mixture is kneaded is maintained in a reduced-pressure atmosphere, and a high-hardness coating layer is formed on the rotary blade portion.

JP 2000-153514 A JP 2008-168609 A JP 2010-221737 A JP-A-5-124021 JP 2008-132752 A

When producing a honeycomb formed body by extruding a kneaded material containing silicon carbide powder, silicon carbide is extremely hard, so that not only heat is generated by contact with the mold, but also blades constituting the screw, etc. Heat tends to be generated due to friction, and therefore the temperature of the kneaded product tends to be high, and when the wet mixture is pushed out of the mold, a difference occurs in the moving speed between the central part and the peripheral part of the mold, and as a result, There is a problem that shape distortion occurs in the extruded continuous honeycomb molded body.

Patent Document 1 describes a method of controlling the outer peripheral temperature and the center temperature of a ceramic molded body in order to prevent shape distortion from occurring in an extruded honeycomb molded body. When a honeycomb formed body is manufactured by continuous extrusion, the outer peripheral temperature of the continuously formed honeycomb formed body can be easily measured using a non-contact thermometer or the like. However, in order to measure the center temperature of the honeycomb formed body, the continuously formed honeycomb formed body must be cut, and it is difficult to measure quickly. Therefore, with the method described in Patent Document 1, it is difficult to quickly adjust the temperature of the dough based on the difference between the obtained outer peripheral temperature and the center temperature.

Patent Document 2 describes that extrusion is performed in the same manner as described above, but does not describe a problem caused by the temperature of the wet mixture described above. Patent Document 3 describes that a homogeneous honeycomb formed body is produced by controlling the size and pitch of the rotary blades of a screw constituting the extrusion molding machine, and the generation of cracks after firing is prevented. However, the temperature of the wet mixture introduced into the mold has not been studied, and it is difficult to prevent the occurrence of distortion due to the temperature of the wet mixture only by the method described in Patent Document 3.

In Patent Document 4, the formed honeycomb formed body is frozen to prevent the deformation of the generated formed body after forming, but the temperature distribution of the wet mixture introduced into the mold is not studied. Since the distortion caused by the temperature of the wet mixture has already occurred when leaving the mold, the method described in Patent Document 4 prevents the occurrence of the shape distortion of the honeycomb formed body caused by the temperature of the wet mixture. Difficult to do.

Patent Document 5 also describes that a honeycomb formed body is produced by extrusion using a screw provided with rotating blades, but the temperature distribution of the wet mixture introduced into the mold has been studied. Absent.

As a result of intensive studies in view of the above problems, the present inventors have prevented shape distortion occurring in the extruded honeycomb molded body by controlling the temperature of the tip portion provided with the die of the extrusion molding apparatus. The present invention has been found.

That is, the extrusion molding apparatus of the present invention produces a kneaded product by kneading a raw material charging port for charging a raw material consisting of a wet mixture containing silicon carbide powder and a wet mixture charged in the raw material charging port with a screw. A kneading part for conveying the kneaded product to the extrusion molding part, and a tip part provided with a mold, and the kneaded material conveyed from the kneading part is pushed into the mold at the tip part by a screw. The extruded portion for producing a continuous honeycomb formed body in which a large number of through holes are arranged in the longitudinal direction by extrusion through the mold, and the produced continuous honeycomb formed body is cut into a predetermined length, An extrusion molding apparatus comprising a conveying unit that conveys the cut honeycomb formed body to the next step, and flowing water for cooling the kneaded material at the tip portion by circulating cooling water therein Piping is arranged, and the running water pipe is connected to the running water pipe for inflowing the running water into the tip portion, and the draining water pipe for discharging the running water from the tip portion, A flow rate control mechanism for controlling the flow rate of the circulating cooling water is disposed in at least one of the inflowing water pipe and the flowing water pipe, and the produced honeycomb formed At least one height sensor for measuring the height in the direction perpendicular to the extrusion direction of the body is arranged, and based on the height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor. The flow rate of the cooling water is controlled by the flow rate control mechanism.

Here, the shape distortion generated in the honeycomb formed body will be described.
The shape of the cross section perpendicular to the longitudinal direction of the honeycomb formed body is a substantially quadrangular shape, and is a shape connected by four sides, which are the upper side, the two side sides, and the lower side. Four sides are curved. The outline of the cross-sectional shape of the honeycomb formed body in this case is a contracted quadrangle whose four sides are curved inward, or a swollen quadrangle whose four sides are curved outward.
When extruding the honeycomb formed body, if the temperature of the kneaded material is suitable, shape distortion does not occur, and the four sides forming the substantially square shape are straight.
When the temperature of the kneaded product is relatively high, the temperature of the central portion is likely to be lower than the temperature of the peripheral portion, and the peripheral portion is likely to move, so the cross-sectional area of the through hole in the peripheral portion is relatively large. As a result, the above-described contraction rectangle is obtained. That is, it means that the kneaded product needs to be cooled.
When the temperature of the kneaded product is relatively low, the temperature of the central portion where the temperature is difficult to decrease is relatively higher than the temperature of the peripheral portion, and the vicinity of the central portion is easily moved. For this reason, the cross-sectional area of the through-hole in the vicinity of the central portion is increased, and as a result, the above-described swelling quadrangle is obtained. That is, it means that the kneaded product is excessively cooled.
Furthermore, if the temperature difference between the central portion and the peripheral portion is large, the shape distortion of the honeycomb formed body increases.
That is, as the temperature of the peripheral portion becomes relatively higher than the temperature of the central portion, the curve forming the above-described contraction rectangle becomes a steep curve.
Further, as the temperature of the central portion becomes relatively higher than the temperature of the peripheral portion, the curve forming the above-described swollen square becomes a steep curve.

According to the extrusion molding apparatus, a flowing water pipe for allowing cooling water to pass therethrough is disposed at the tip of the extrusion molding portion, and the flowing water pipe flows the flowing water into the tip. A flow rate control mechanism for controlling the flow rate of the cooling water that is circulated and connected to the flowing water piping for inflowing and the draining water piping for discharging the flowing water from the tip end is provided with the inflowing flowing water. And at least one of a height sensor for measuring a height in a direction perpendicular to the extrusion direction of the produced honeycomb formed body is disposed in at least one of the pipe for flowing water and the pipe for flowing water. One unit is arranged, and the flow rate of the cooling water is controlled by the flow rate control mechanism based on the height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor. Of kneaded material Degrees can be kept in a predetermined range, it is possible to the shape described above strain honeycomb molded body to be produced is prevented from occurring.

In the extrusion molding apparatus of the present invention, two height sensors are arranged, the heights of two different locations of the honeycomb molded body are measured, and the cooling water is measured based on the difference in height between the two measured locations. It is desirable to control the flow rate.

According to the above extrusion molding apparatus, when shape distortion occurs in the extruded honeycomb formed body, when the heights of two different places are measured, the heights are different. Based on the difference in height, it is judged whether the temperature of the kneaded product is high or low. If the temperature of the kneaded product is high, the flow rate of the cooling water is increased, and if the temperature of the kneaded product is low, cooling is performed. By reducing the flow rate of water, the temperature of the kneaded product to be extruded can be maintained within a predetermined range.

In the extrusion molding apparatus of the present invention, the shape of the cross section perpendicular to the longitudinal direction of the honeycomb formed body is a substantially square shape, and the height sensor on one side is configured such that the height sensor at the end of the upper side of the substantially square shape is provided every predetermined time. The height (h1) in the direction perpendicular to the extrusion direction of the honeycomb formed body is measured, and the other height sensor detects the extrusion direction of the honeycomb formed body at the middle portion of the upper side of the substantially square shape at every predetermined time. The height (h2) in the vertical direction is measured, and the distance difference (D) is calculated from the height (h1) and the height (h2) measured at the same time based on the following formula (1). Then, the amount of change per unit time of the distance difference (D) is calculated from the distance difference (D) calculated at each time, and the flow rate control mechanism is such that the distance difference (D) is a positive value. The amount of change in the distance difference (D) per unit time is positive If the flow rate of the cooling water is increased, the distance difference (D) is a negative value, and the amount of change in the distance difference (D) per unit time is a negative value, the cooling water It is desirable to reduce the flow rate.
D = h1-h2 (1)

When the flow rate of the cooling water is constant, the shape distortion of the extruded honeycomb formed body proceeds with time.
Therefore, by measuring the distance difference (D) over time and calculating the amount of change in the distance difference (D) per unit time, the temperature of the kneaded product is becoming relatively high or low. Can be determined.
That is, when the amount of change in the distance difference (D) per unit time is a positive value, it means that the temperature of the kneaded product is becoming relatively high, and the distance difference per unit time (D) When the amount of change is a negative value, it means that the temperature of the kneaded product is becoming relatively low.

The relationship between the shape distortion of the honeycomb formed body, the value of the distance difference (D), and the distance difference (D) change amount per unit time is as follows.
When the distance difference (D) is a positive value and the amount of change in the distance difference (D) per unit time is a positive value, it means that the shape distortion of the contraction rectangle is progressing.
If the distance difference (D) is a positive value and the amount of change in the distance difference (D) per unit time is a negative value, it means that the shape distortion of the contraction rectangle is being eliminated.
When the distance difference (D) is a negative value and the change amount of the distance difference (D) per unit time is a negative value, it means that the shape distortion of the swollen square is progressing.
When the distance difference (D) is a negative value and the change amount of the distance difference (D) per unit time is a positive value, it means that the shape distortion of the swollen square is being eliminated.

According to the above extrusion molding apparatus, it is determined from the relationship between the distance difference (D) and the amount of change in the distance difference per unit time (D) whether the shape distortion is progressing or disappearing. Can be prevented from occurring by controlling the flow rate of the cooling water.
That is, when the distance difference (D) is a positive value and the change amount of the distance difference (D) per unit time is a positive value, the flow rate of the cooling water is increased and the distance difference (D) is negative. When the amount of change in the distance difference (D) per unit time is a negative value, by reducing the flow rate of the cooling water,
The temperature of the kneaded product can be maintained within a predetermined range, and the occurrence of shape distortion in the honeycomb formed body can be prevented.

As described above, when the flow rate of the cooling water is controlled over time in accordance with the change in the shape of the honeycomb formed body over time, the temperature of the kneaded material does not change abruptly. The structure is stable because it does not change suddenly.

In the extrusion molding apparatus of the present invention, the shape of the cross section perpendicular to the longitudinal direction of the honeycomb molded body is substantially a square, and the height sensor is in the extrusion direction of the honeycomb molded body in the middle portion of the upper side of the substantially square. On the other hand, the height in the vertical direction is measured at a first time (t1) and a second time (t2) after a predetermined time has elapsed from the first time, and the first time (t1) is measured. ), The height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor is defined as the height (H _t1 ) at the first time, and the height at the second time (t2). When the height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor is the height at the second time (H _t2 ), and each side constituting the substantially square is a straight line Of the honeycomb in the middle part of the upper side of the substantially rectangular shape. The height in the direction perpendicular to the extrusion direction of the feature is defined as height (H _b ), and the cooling water flowing from the first time (t1) to the second time (t2) per unit time Assuming that the flow rate is a flow rate (V _{t1 -t2} ), the flow rate control mechanism has a height (H _t1 ) at the first time higher than a height (H _t2 ) at the second time, and When the height (H _t2 ) at the second time is lower than the height (H _b ), the cooling water unit is measured after the height (H _t2 ) at the second time is measured. The flow rate per time is increased from the flow rate (V _{t1 -t2} ), the height (H _t1 ) at the first time is lower than the height (H _t2 ) at the second time, and height at 2 time if _{(H t2)} is greater than the height _{(H b),} the measurement of the height at the second time _{(H t2)} , It is desirable to reduce than the flow rate per unit of the cooling water times the flow rate (V _t1-t2).

Assuming an outline of a cross section perpendicular to the longitudinal direction of the honeycomb formed body, when a shape distortion occurs, the cross-sectional shape becomes a contracted quadrangle or a swollen quadrangle.
Further, when the temperature of the kneaded product is suitable, no shape distortion occurs in the honeycomb formed body, and the side forming the cross section perpendicular to the longitudinal direction of the honeycomb formed body is substantially a straight line. The height of a predetermined portion of the honeycomb formed body at this time is defined as a height (H _b ).
When the temperature of the kneaded product is relatively high and the shape of the cross section of the honeycomb molded body is a contracted quadrangle, the curve forming the contracted quadrangle is bent inward, so the height of a predetermined portion of the honeycomb molded body is It becomes lower than the height (H _b ).
When the temperature of the kneaded product is relatively low and the cross-sectional shape of the honeycomb molded body is a swollen quadrangle, the curve forming the swollen quadrangle is bent outward, so the height of a predetermined portion of the honeycomb molded body is high. Higher than (H _b ).

Further, when the flow rate of the cooling water is constant, the shape distortion of the extruded honeycomb formed body proceeds with time.
Therefore, at the height (H _t1 ) of the predetermined portion of the honeycomb formed body at the first time (t1) and at the second time (t2) after a predetermined time has elapsed from the first time (t1). It is possible to determine whether the temperature of the kneaded product is becoming relatively high or low by measuring the height (H _t2 ) of a predetermined portion of the honeycomb formed body.
That is, the fact that the height (H _t1 ) at the first time is higher than the height (H _t2 ) at the second time means that the temperature of the kneaded product is becoming relatively high, That the height (H _t1 ) at the first time is lower than the height (H _t2 ) at the second time means that the temperature of the kneaded material is becoming relatively low.

From the above, the relationship between (H _b ), (H _t1 ), and (H _t2 ) is as follows.
The height (H _t1 ) at the first time is higher than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is the height (H _b ). If it is lower than that, it means that the shape distortion of the shrinking rectangle is progressing.
The height (H _t1 ) at the first time is lower than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is the height (H _b ). If it is lower than that, it means that the shape distortion of the shrinking rectangle is being eliminated.
The height (H _t1 ) at the first time is lower than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is the height (H _b ). If it is higher than that, it means that the shape distortion of the swollen square is progressing.
The height (H _t1 ) at the first time is higher than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is the height (H _b ). If it is higher, it means that the shape distortion of the swollen square is being eliminated.

According to the extrusion molding apparatus, it is determined whether the shape distortion is progressing or disappearing from the relationship of (H _b ), (H _t1 ), and (H _t2 ), and the shape distortion is progressing. In some cases, the flow rate of cooling water can be controlled to prevent shape distortion.
That is, assuming that the flow rate per unit time of the cooling water flowing from the first time (t1) to the second time (t2) is a flow rate (V _{t1 -t2} ), the height at the first time ( H _t1) is the height of the second time _{(H t2)} higher than, and, if the second time in the height _{(H t2)} is the height _{(H b)} is lower than the second After measuring the height (H _t2 ) at the time, the flow rate per unit time of the cooling water is increased from the flow rate (V _{t1 -t2} ), and the height (H _t1 ) at the first time is the second. If the height (H _t2 ) at the second time is lower than the height (H _t2 ) and the height (H _t2 ) at the second time is higher than the height (H _b ), the height at the second time is after measurement of the (H _t2), the flow rate per unit of cooling water time to reduce than the flow rate (V _t1-t2), the temperature of the kneaded material Can be kept in a predetermined range, the shape distortion in the honeycomb molded body can be prevented from occurring.
The flow rate of the cooling water is preferably controlled immediately after measuring the height of a predetermined portion of the honeycomb formed body at the second time.

As described above, when the flow rate of the cooling water is controlled over time in accordance with the change in the shape of the honeycomb formed body over time, the temperature of the kneaded material does not change abruptly. The structure is stable because it does not change suddenly.

A method for manufacturing a honeycomb formed body of the present invention is a method for manufacturing a honeycomb formed body using the above-described extrusion molding apparatus, and by charging a raw material made of a wet mixture containing silicon carbide powder from a raw material input port, A continuous honeycomb molded body producing step for producing a continuous honeycomb molded body in which a number of through-holes are arranged in the longitudinal direction by performing extrusion molding through a mold of the extrusion molding section; Cutting into a honeycomb molded body and measuring the height in a direction perpendicular to the extrusion direction of the honeycomb molded body with a height sensor while the cut honeycomb molded body is conveyed by a conveyance unit A flow rate control step for controlling the flow rate of the cooling water by a flow rate control mechanism based on the height measurement step and the height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor Characterized in that it comprises a.

According to the method for manufacturing a honeycomb molded body, the flow rate of the cooling water is controlled by the flow rate control mechanism based on the height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor. The temperature of the kneaded material passing through the mold can be maintained within a predetermined range, and the occurrence of shape distortion in the produced honeycomb formed body can be prevented.

In the method for manufacturing a honeycomb formed body of the present invention, the height of two different portions of the honeycomb formed body is measured by two height sensors, and the cooling water is measured based on the difference between the measured heights of the two positions. It is desirable to control the flow rate.

According to the above method for manufacturing a honeycomb formed body, when a shape distortion occurs in the extruded honeycomb formed body, there is a difference in height when two different heights are measured. If the temperature of the kneaded product is high or low based on the difference in height measured by the above, if the temperature of the kneaded material is high, the flow rate of cooling water is increased, and the temperature of the kneaded material is low The temperature of the kneaded product to be extruded can be kept within a predetermined range by decreasing the flow rate of the cooling water.

In the method for manufacturing a honeycomb molded body of the present invention, the shape of the cross section perpendicular to the longitudinal direction of the honeycomb molded body is substantially a square, and in the height measurement step, one height sensor is used for every predetermined time. The height (h1) in the direction perpendicular to the extrusion direction of the honeycomb formed body at the end of the upper side of the substantially quadrilateral is measured, and the other side of the upper side of the substantially quadrilateral is measured by the other height sensor. The height (h2) in the direction perpendicular to the extrusion direction of the honeycomb formed body in the intermediate portion is measured, and the height (h1) and the height (h2) measured at the same time based on the following formula (1) ) From the distance difference (D) calculated at each time, the amount of change per unit time of the distance difference (D) is calculated. The control mechanism uses the distance difference (D Is a positive value, and the amount of change in the distance difference (D) per unit time is a positive value, the flow rate of the cooling water is increased, and the distance difference (D) is a negative value, When the change amount of the distance difference (D) per unit time is a negative value, it is desirable to reduce the flow rate of the cooling water.
D = h1-h2 (1)

As described above, it can be determined from the relationship between the distance difference (D) and the amount of change in the distance difference per unit time (D) whether the shape distortion is progressing or is being eliminated.
According to the above method for manufacturing a honeycomb formed body, the temperature of the kneaded product is set to a predetermined value by controlling the flow rate of the cooling water based on the distance difference (D) and the amount of change in the distance difference per unit time (D). The range can be maintained, and the occurrence of shape distortion in the honeycomb formed body can be prevented.

In the method for manufacturing a honeycomb molded body, as described in the extrusion molding apparatus of the present invention, the shape distortion generated in the honeycomb molded body can be captured at an initial stage.
Therefore, by controlling the flow rate of the cooling water on the basis of the distance difference (D) and the change amount of the distance difference per unit time (D), it is possible to effectively generate shape distortion in the honeycomb formed body. Can be prevented.
Can be prevented.

In the method for manufacturing a honeycomb formed body of the present invention, the shape of the cross section perpendicular to the longitudinal direction of the honeycomb formed body is a substantially square shape, and in the height measuring step, the height sensor is used to determine the middle of the upper side of the substantially square shape. The height in the direction perpendicular to the extrusion direction of the honeycomb molded body in the portion is a first time (t1) and a second time (t2) after a predetermined time has elapsed from the first time. The height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor at the first time ( _t1 ) is _defined as the height (H _t1 ) at the first time, and The height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor at the second time (t2) is defined as the height (H _t2 ) at the second time, thereby forming the substantially square shape. When each side is a straight line, The height in the direction perpendicular to the extrusion direction of the honeycomb formed body in the middle part of the upper side of the square is defined as height (H _b ), and the period from the first time (t1) to the second time (t2). Assuming that the flow rate per unit time of the cooling water flowing in the flow rate is V ( _t1-t2 ), in the flow rate control step, the height ( _Ht1 ) at the first time is set to the second time by the flow rate control mechanism. time in height (H _t2) higher than, and, when the height at the second time (H _t2) is the height (H _b) less than, in the second time After the measurement of the height (H _t2 ), the flow rate of the cooling water per unit time is increased from the flow rate (V _{t1 -t2} ), and the height (H _t1 ) at the first time is the second value. Is lower than the height at the time (H _t2 ), and the height (H _t2 ) at the second time is higher. When the height is higher than the height (H _b ), after measuring the height (H _t2 ) at the second time, the flow rate per unit time of the cooling water is higher than the flow rate (V _{t1 -t2} ). It is desirable to reduce it.

As described in the extrusion molding apparatus of the present invention, it can be determined from the relationship between (H _b ), (H _t2 ) and (H _t2 ) whether the shape distortion is progressing or is being eliminated. . Therefore, when the shape distortion is progressing, the generation of the shape distortion can be prevented by controlling the flow rate of the cooling water.
That is, assuming that the flow rate per unit time of the cooling water flowing from the first time (t1) to the second time (t2) is a flow rate (V _{t1 -t2} ), the height at the first time ( H _t1) is the height of the second time _{(H t2)} higher than, and, if the second time in the height _{(H t2)} is the height _{(H b)} is lower than the second After measuring the height (H _t2 ) at the time, the flow rate per unit time of the cooling water is increased from the flow rate (V _{t1 -t2} ), and the height (H _t1 ) at the first time is the second. If the height (H _t2 ) at the second time is lower than the height (H _t2 ) and the height (H _t2 ) at the second time is higher than the height (H _b ), the height at the second time is after measurement of the (H _t2), the flow rate per unit of cooling water time to reduce than the flow rate (V _t1-t2), the temperature of the kneaded material Can be kept in a predetermined range, the shape distortion in the honeycomb molded body can be prevented from occurring.
The flow rate of the cooling water is preferably controlled immediately after measuring the height of a predetermined portion of the honeycomb formed body at the second time.

FIG. 1 is a cross-sectional view schematically showing an example of an extrusion molding apparatus according to the first embodiment of the present invention. FIG. 2 is a perspective view schematically showing an example of a tip portion constituting the extrusion molding apparatus according to the first embodiment of the present invention. Fig.3 (a) is a perspective view which shows typically an example of the honeycomb molded object produced with the extrusion molding apparatus which concerns on 1st embodiment of this invention. FIG.3 (b) is the sectional view on the AA line of Fig.3 (a). FIG. 4 (a) is a cross-sectional view schematically showing an example of a cross section obtained by cutting a honeycomb molded body extruded at a relatively high temperature without being sufficiently cooled, in a direction perpendicular to the longitudinal direction. FIG. FIG. 4B is a cross-sectional view schematically showing an example of a cross section obtained by cutting a honeycomb molded body obtained by extruding at a relatively low temperature after the kneaded product is excessively cooled, in a direction perpendicular to the longitudinal direction. is there. FIG. 5 (a) shows a height in a direction perpendicular to the extrusion direction of the honeycomb molded body having a cross-sectional shape of a shrinkage quadrangle, which is measured by a height sensor constituting the extrusion molding apparatus according to the first embodiment of the present invention. It is a schematic diagram which shows an example of thickness typically. FIG. 5B shows a height in a direction perpendicular to the extrusion direction of the honeycomb molded body having a cross-sectional shape of a swelled square, which is measured by a height sensor constituting the extrusion molding apparatus according to the first embodiment of the present invention. It is a schematic diagram which shows an example of thickness typically. FIG. 6 schematically shows an example of a cross section of the conveying member of the extrusion molding apparatus according to the first embodiment of the present invention and the honeycomb formed body mounted on the conveying member cut in a direction perpendicular to the conveying direction of the conveying member. It is a perspective view shown. FIG. 7 is a chart diagram of a mechanism for controlling the temperature of the kneaded product of the extrusion molding apparatus according to the first embodiment of the present invention. FIGS. 8A to 8D are graphs schematically showing an example of a function for determining the flow rate of the cooling water in the extrusion molding apparatus according to the first embodiment of the present invention. FIG. 9A is a perspective view schematically showing an example of a honeycomb fired body manufactured from a honeycomb formed body manufactured using the extrusion molding apparatus according to the first embodiment of the present invention. FIG. 9B is a cross-sectional view taken along line BB in FIG. FIG. 10 schematically shows an example of a honeycomb structure manufactured by assembling a plurality of honeycomb fired bodies manufactured from a honeycomb formed body manufactured using the extrusion molding apparatus according to the first embodiment of the present invention. It is a perspective view shown. FIG. 11 is a graph schematically showing an example of a change with time of the distance difference (D) in a honeycomb formed body manufactured using the extrusion molding apparatus according to the second embodiment of the present invention. FIG. 12 is a graph schematically showing an example of a change in height of a predetermined portion of the honeycomb formed body manufactured using the extrusion molding apparatus according to the third embodiment of the present invention with time.

Hereinafter, embodiments of the present invention will be specifically described. However, the present invention is not limited to the following embodiments, and can be applied with appropriate modifications without departing from the scope of the present invention.

(First embodiment)
Hereinafter, a first embodiment which is an embodiment of an extrusion molding apparatus and a method for manufacturing a honeycomb molded body of the present invention will be described.

FIG. 1 is a cross-sectional view schematically showing an example of an extrusion molding apparatus according to the first embodiment of the present invention.

An extrusion molding apparatus 1 according to the first embodiment of the present invention shown in FIG. 1 includes a raw material charging port 2 for charging a raw material made of a wet mixture containing silicon carbide powder, and a wet mixture charged from the raw material charging port 2. Kneaded with a screw to produce a kneaded product, and the kneaded product is conveyed from the kneading unit 3, including a kneading unit 3 that conveys the kneaded product to the extrusion molding unit 4, and a tip 40 having a mold 41. Is extruded into the die 41 of the tip 40 with a screw and extruded through the die 41 to produce an extruded portion 4 that produces a continuous honeycomb molded body 60 in which a large number of through holes are arranged in the longitudinal direction. The continuous honeycomb formed body 60 is cut into a predetermined length, and the transport unit 5 is provided to transport the cut honeycomb formed body 61 to the next process.
The tip 40 is provided with a flowing water pipe 42 for cooling the kneaded product by passing cooling water through the inside thereof, and the flowing water pipe 42 is a flowing water for inflow for flowing water into the tip. A flow rate control mechanism 43 that controls the flow rate of the circulating cooling water connected to the piping 45 for discharging and the flowing water piping 46 for discharging the flowing water from the tip is disposed in the flowing water piping 45. Has been.
At least one height sensor 51 for measuring the height of the manufactured honeycomb formed body 61 is arranged in the transport unit 5, and based on the height of the honeycomb formed body 61 measured by the height sensor 51, The flow rate of the cooling water can be controlled by adjusting the opening / closing angle of a control valve built in the flow rate control mechanism 43.

The kneading part 3 which comprises the extrusion molding apparatus 1 which concerns on 1st embodiment of this invention is demonstrated.
The kneading part 3 is composed of a two-stage screw mixer, an upper stage screw mixer 100 and a lower stage screw mixer 200, in which a screw having a screw shaft and screw blades (blade part) is provided. .

A raw material inlet 2 is disposed at one end of the upper screw mixer 100, and a kneading push roller for pushing the wet mixture into the upper screw mixer 100 is received in the receiving port 101 below the raw material inlet 2. 102 is provided.

The upper screw mixer 100 includes a feed screw 111 having a role of moving the wet mixture as well as kneading, an entanglement screw 112 mainly for kneading the wet mixture, and a W provided further on the tip. A kneading screw 110 composed of a blade screw 113 is provided. In the feed screw 111, a kneaded product can be produced by kneading the wet mixture, and the kneaded product can be pushed forward.

At the other end of the upper screw mixer 100, a die (die) 120 having a large number of through holes is arranged, and the kneaded material after passing through the W blade screw 113 is pushed into the die 120. Become. The kneaded product pushed into the die 120 is in a bar-like or udon noodle state.

A decompression chamber 130 is provided in the portion of the die 120 where the kneaded product is extruded, and the inside of the die 120 can be in a decompressed state close to a vacuum.
By kneading in a reduced pressure state close to vacuum, it is possible to prevent bubbles (air) from being caught inside the kneaded product. If bubbles are caught in the kneaded product, defects due to the bubbles are likely to occur in the partition walls and the like when the honeycomb formed body is manufactured.

An upper cutter 140 as a cutting member is provided in the decompression chamber 130 and in the vicinity of the die 120. That is, the upper cutter 140 exists inside the decompression chamber 130, and reciprocates up and down in the vicinity of the die 120 by the air cylinder provided in the decompression chamber 130, and is pushed out from the die 120 into a udon noodle shape (bar shape). The kneaded product can be cut into fine lumps.

A large number of cut small chunks are taken into the lower screw mixer 200 immediately below.
Since the configuration of the lower screw mixer 200 is the same as that of the upper screw mixer 100, a detailed description thereof will be omitted.

The kneaded material taken into the lower screw mixer 200 is kneaded in the same manner as with the upper screw mixer 100 and taken into the extrusion screw unit 400.

In the extrusion apparatus 1 according to the first embodiment of the present invention, the kneading unit 3 is composed of two screw mixers, and the wet mixture can be kneaded by each of these screw mixers. In the extrusion molding apparatus of the present invention, the number of screw mixers in the kneading unit 3 is not particularly limited, but is preferably 2 to 4 units. If one unit is used, it may be difficult to sufficiently knead. Even if five units or more are provided, the degree of kneading does not change greatly, which is economically disadvantageous.

Further, in the extrusion molding apparatus 1 according to the first embodiment of the present invention shown in FIG. 1, the wet mixture is pushed into each screw mixer by the kneading push roller 102. It may be pushed in, or may simply be formed with a slot. Moreover, the combination of the screw provided inside each screw mixer is not limited to the combination mentioned above, For example, it may be comprised only from the field screw and the other combination may be sufficient.

The constituent materials of the kneading push roller 102 and the kneading screw 110 are not particularly limited, but it is desirable to use tungsten carbide.

It is desirable to adjust the size of the core material of the kneading push roller 102, the size of the blades, the space between the blades, and the rotation speed of the rollers according to the composition of the wet mixture.

It is desirable to adjust the shaft size, blade size, blade angle, and blade interval of the kneading screw 110 according to the composition of the wet mixture.

Next, the extrusion molding unit 4 will be described.
The extrusion molding part 4 includes an extrusion screw part 400 and a tip part 40.

A large number of small chunks extruded and cut from the lower screw mixer 200 fall into the receiving port 401 of the extrusion screw portion 400 immediately below and are pushed into the extrusion screw portion 400 by the kneading push roller 402. .
The extrusion screw unit 400 includes an extrusion screw 410 including a feed screw 411 and a W blade screw 413 provided at the tip thereof. The kneaded product is extruded by the extrusion screw 410.
A tip portion 40 is connected to an end portion of the extrusion screw portion 400 through which the kneaded material is extruded.
A mesh filter for filtering the kneaded material may be disposed between the tip portion 40 and the extrusion screw portion 400.

The constituent materials of the kneading push roller 402 and the extrusion screw 410 are not particularly limited, but it is desirable to use tungsten carbide.

It is desirable to adjust the size of the core material of the kneading push roller 402, the size of the blades, the interval between the blades, and the rotation speed of the rollers according to the composition of the wet mixture.

It is desirable to adjust the shaft size, blade size, blade angle, and blade spacing of the extrusion screw 410 according to the composition of the wet mixture.

FIG. 2 is a perspective view schematically showing an example of a tip portion constituting the extrusion molding apparatus according to the first embodiment of the present invention.
A mold 41 and a casing 44 are disposed at the distal end portion 40. The kneaded product extruded by the extrusion screw 410 is continuously extruded from the mold 41 through the casing 44 to form a substantially rectangular column-shaped continuous honeycomb molded body 60 in which a large number of cells are formed in the longitudinal direction.

In the process in which the kneaded product is extruded by the extrusion screw 410, the kneaded product comes into contact with not only the mold 41 but also the blades constituting the extrusion screw 410, the inner wall of the casing 44, and the like. Since the kneaded material contains extremely hard silicon carbide powder, heat is likely to be generated by the above contact (friction), and the temperature of the kneaded material tends to increase. When the temperature of the kneaded material is relatively high, the temperature of the central portion of the mold 41 tends to be lower than the temperature of the peripheral portion, and the moving speed of the kneaded material in the peripheral portion becomes relatively fast. In particular, the kneaded material in the peripheral portion comes into contact with the casing 44 having a regularity, and a lot of frictional heat is generated in this portion. Therefore, the difference between the temperature and the moving speed is increased.
Therefore, when the kneaded product is extruded by the mold, a difference occurs in the speed at which the kneaded product is extruded and moved between the central portion of the mold 41 and the peripheral portion. As a result, shape distortion occurs in the extruded continuous honeycomb molded body 60. Therefore, the cross-sectional area of the through-hole in the peripheral portion is relatively large, and the cross section perpendicular to the longitudinal direction of the continuous honeycomb molded body 60 formed as a result is a contracted quadrangle.

In order to prevent the occurrence of such distortion, the flowing water pipe 42 covers the periphery of the mold 41 and the casing 44 at the distal end portion 40. The mold 41 and the casing 44 can be cooled by circulating the cooling water through the flowing water pipe 42 (in FIG. 2, the flow of the cooling water is indicated by an arrow). Thereby, the temperature of a kneaded material can be lowered | hung.
However, when the flow rate of the cooling water increases and the mold 41 and the casing 44 are excessively cooled, the kneaded material is excessively cooled.
When the temperature of the kneaded product is relatively low, the temperature of the central portion of the mold 41 and the casing 44 that is difficult to decrease becomes relatively higher than the temperature of the peripheral portion, and the moving speed of the kneaded product near the central portion is high. Relatively fast. In particular, since the flowing water pipe 42 covers the periphery of the mold 41 and the casing 44, the cooling water flows through the flowing water pipe 42, whereby the kneaded material is cooled from the outside. Therefore, the difference between the temperature and the moving speed is increased.
Therefore, the cross-sectional area of the through hole near the center portion is increased, and the cross section perpendicular to the longitudinal direction of the continuous honeycomb formed body 60 formed as a result is a swollen square.
In order to prevent such shape distortion due to excessive cooling, the flowing water pipe 42 includes an inflow water pipe 45 for flowing water into the tip portion, and a discharge pipe for discharging the flowing water from the tip portion. A flow rate control mechanism 43 that is connected to the running water piping 46 and controls the flow rate of the circulating cooling water is disposed in the running water piping 45. Control of the flow rate of the cooling water by the flow rate control mechanism 43 adjusts the opening / closing angle of a control valve built in the flow rate control mechanism 43 based on the height of the honeycomb formed body 61 measured by a height sensor 51 described later. Etc.
Adjusting the opening / closing angle of the control valve built in the flow rate control mechanism 43 means increasing the opening / closing angle of the control valve or decreasing the opening / closing angle of the control valve. Increasing the opening / closing angle of the control valve means increasing the flow rate of the cooling water, and decreasing the opening / closing angle of the control valve means decreasing the flow rate of the cooling water.
The flow rate of the cooling water can be easily controlled by adjusting the opening / closing angle of the control valve.
It is possible to confirm by measuring in advance what amount of cooling water flows when the control valve is opened and closed.
Further, when the control valve is completely opened, the flow rate of the cooling water becomes maximum, and when the control valve is completely closed, the cooling water does not flow. In the extrusion apparatus 1 according to the first embodiment of the present invention, the flow rate of the cooling water by the flow rate control mechanism 43 may be controlled only by completely opening the control valve and completely closing the control valve. In this case, the kneaded product is cooled by on / off control using cooling water.

Next, the conveyance unit 5 will be described.
The conveying unit 5 measures the height of a conveying member 52 that conveys the extruded continuous honeycomb molded body 60, a cutting member 53 that cuts the continuous honeycomb molded body 60 into a predetermined length, and the honeycomb molded body 61. The height sensor 51 is provided, and the conveying member 52 can convey the honeycomb formed body 61 cut to a predetermined length to the next process.

The height sensor 51 can measure the height of a predetermined portion of the honeycomb formed body 61.
As long as the height sensor 51 can measure the height of a predetermined portion of the honeycomb formed body 61, the number and measuring method are not particularly limited, but a laser displacement sensor is used to irradiate a predetermined position of the honeycomb formed body 61 with laser. It is desirable to measure the height by laser reflection. Alternatively, the height may be measured by taking an image of the end face of the honeycomb formed body 61 from a direction parallel to the longitudinal direction of the honeycomb formed body 61 and performing image processing. The details of the predetermined portion of the honeycomb formed body 61 to be measured will be described later.

When the height of the honeycomb formed body 61 measured by the height sensor 51 does not satisfy a predetermined standard, that is, when a sign of shape distortion is recognized in the honeycomb formed body 61, the measured value is fed back and flowing water Adjustment of the opening / closing angle of the control valve built in the flow rate control mechanism 43 arranged in the piping 42 is performed. Thereby, it is possible to prevent an unacceptable shape distortion from occurring in the honeycomb formed body 61 in advance.

The conveying member 52 can convey the continuous honeycomb molded body 60 extruded from the extrusion molding unit 4 to the place where the cutting member 53 is disposed. Examples of the form of the conveying member 52 include a belt conveyor.

The cutting member 53 has a function of cutting the continuous honeycomb formed body 60 into a predetermined length. Although it does not specifically limit as a form of a cutting member, For example, the cutter in which the blade was formed, a laser, a linear body, etc. are mentioned. In consideration of the contact area with the continuous honeycomb molded body 60 and the running cost, a linear body is desirable among these. When the linear body is used, since the contact area with the ceramic molded body is extremely small, even if the cells of the continuous honeycomb molded body 60 come into contact with each other, deformation such as cracks, shear deformation, and chipping are not caused. In addition, the running cost can be kept low because an accessory device such as a laser is not required.

When the cutting member 53 is a linear body, the constituent material of the linear body is not particularly limited, but is preferably a metal wire or a metal wire coated with a resin.
Further, it is desirable that the linear body is cut from the top to the bottom by cutting the continuous honeycomb formed body 60 into a predetermined length. At this time, the continuous honeycomb formed body 60 is cut into the continuous honeycomb formed body 60 by moving the linear body in conjunction with the direction in which the continuous honeycomb formed body 60 is conveyed and moving the linear body. It is desirable to cut in a direction perpendicular to the longitudinal direction of 60. By cutting in this way, the end surface of the honeycomb formed body 61 can be made perpendicular to the direction parallel to the longitudinal direction of the honeycomb formed body 61.

The constituent material of the contact portion of the conveying member 52 that contacts the continuous honeycomb formed body 60 and the honeycomb formed body 61 is not particularly limited, and examples thereof include resins such as natural rubber, nylon, urethane, and polyester. Further, the contact portion may have a sponge shape, a shape such that long fibers are intertwined, or the like, and a shape that can be elastically deformed when a predetermined stress is applied. With such a shape, when the cutting member 53 passes through the inside of the continuous honeycomb formed body 60 and reaches the lower surface of the honeycomb formed body, the cutting member 53 can further sink into the contact portion. The continuous honeycomb molded body 60 can be completely cut.

When a shape distortion occurs so that the cross-sectional shape of the honeycomb formed body 61 becomes a swollen quadrangle, a side forming the swollen quadrangle is bent outward. Therefore, if the conveying member 52 is a flat surface, the honeycomb formed body 61 conveyed by the conveying member 52 is inclined. When there is such an inclination, it becomes difficult to measure the height of the honeycomb formed body 61. Therefore, the conveyance member 52 may be provided with a recess 54 for preventing the honeycomb formed body 61 from being inclined when a shape distortion occurs such that the cross-sectional shape of the honeycomb formed body 61 becomes a swollen square. desirable. The concave portion 54 provided in the transport member 52 will be described in detail later.

Next, the honeycomb formed body 61 produced by the extrusion molding apparatus according to the first embodiment of the present invention will be described.

Fig.3 (a) is a perspective view which shows typically an example of the honeycomb molded object produced with the extrusion molding apparatus which concerns on 1st embodiment of this invention. FIG.3 (b) is the sectional view on the AA line of Fig.3 (a).

In the honeycomb formed body 61 shown in FIGS. 3A and 3B, a large number of cells 62 are arranged in parallel in the longitudinal direction with a cell wall 63 therebetween, and an outer peripheral wall 64 is formed around the cell 62.

As shown in FIG. 3 (b), the honeycomb molded body 61 extruded by appropriately controlling the temperature of the kneaded product has a substantially square cross-sectional shape, and its outline is composed of four substantially straight lines at four vertices. It becomes a tied shape.

As described above, the continuous honeycomb formed body 60 is formed by extruding a kneaded material containing silicon carbide powder. Since the honeycomb formed body 61 is produced by cutting the continuous honeycomb formed body 60 with a predetermined length, the cross-sectional shape of the continuous honeycomb formed body 60 cut in the direction perpendicular to the longitudinal direction is the same as that of the honeycomb formed body 61. It is the same shape as the cross-sectional shape.

Although it does not specifically limit as a silicon carbide powder contained in a kneaded material, It is desirable to mix | blend the particle | grains from which an average particle diameter differs in a predetermined ratio. That is, 1.0 to 30 μm silicon carbide particles having a relatively large average particle diameter and 0.05 to 1.0 μm silicon carbide particles having a relatively small average particle diameter are mixed in an amount of 1: 0.05. It is desirable to blend so as to have a ratio of ˜1: 0.65. When blended as described above, the pore size and the porosity of the produced honeycomb formed body 61 are suitable. Moreover, in order to adjust a pore diameter and cell wall thickness, you may mix | blend the said ratio and mix | blend the silicon carbide particle from which 3 or more types of average particle diameters differ.

Since the silicon carbide powder is a ceramic material, the honeycomb fired body 71 which is a ceramic body can be fired by heating the manufactured honeycomb formed body 61.

In addition to the silicon carbide powder, the wet mixture may contain other ceramic materials, inorganic particles, inorganic fibers, inorganic binders, organic binders, pore formers, plasticizers, lubricants, dispersants, and the like.

Examples of other ceramic materials include cordierite and alumina titanate.

Examples of the inorganic particles include alumina, silica, zirconia, titania, ceria, mullite, and zeolite. The average particle diameter of the inorganic particles is desirably 0.1 to 10 μm. In addition, it is desirable to add 1 to 40% by weight of the inorganic particles with respect to the total amount of the kneaded product.

Examples of the inorganic fiber include alumina, silica, silicon carbide, alumina silica, glass, potassium titanate, aluminum borate and the like. The fiber length of the inorganic fiber is desirably 0.1 to 10 μm. The inorganic fibers are desirably blended in an amount of 3 to 50% by weight based on the total amount of the kneaded product.

As the inorganic binder, an inorganic sol, a clay sol, or the like can be used. Examples of the inorganic sol include alumina sol, silica sol, titania sol, and water glass. Examples of the clay-based sol include clay, kaolin, montmorillonite, sepiolite, and attapulgite. These may be used alone or in combination of two or more. As for an inorganic binder, it is desirable to mix | blend 2 to 50 weight% with respect to the wet mixture whole quantity.

Examples of the organic binder include synthetic resins such as methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyethylene glycol, phenol resin, and epoxy resin. As for an organic binder, it is desirable to mix | blend 1 to 10 weight% with respect to the kneaded material whole quantity.

Examples of the pore former include acrylic resin and starch. As for a pore making material, it is desirable to mix | blend 5 to 15 weight% with respect to the wet mixture whole quantity.

Examples of the plasticizer include glycerin, and examples of the lubricant include polyoxypropylene alkyl ether and unilube.

Examples of the dispersant include water, an organic solvent (such as benzene), and alcohols such as methanol and ethanol. The dispersant is desirably blended in an amount of 3 to 30% with respect to the total amount of the wet mixture.

Next, the shape distortion of the honeycomb formed body that occurs during extrusion molding will be described.
FIG. 4 (a) is a cross-sectional view schematically showing an example of a cross section obtained by cutting a honeycomb molded body extruded at a relatively high temperature without being sufficiently cooled, in a direction perpendicular to the longitudinal direction. FIG.
FIG. 4B is a cross-sectional view schematically showing an example of a cross section obtained by cutting a honeycomb molded body obtained by extruding at a relatively low temperature after the kneaded product is excessively cooled, in a direction perpendicular to the longitudinal direction. is there.

As shown in FIG. 4 (a), in the honeycomb molded body 80 obtained by extrusion molding at a relatively high temperature without cooling the kneaded product, the profile of the cross section obtained by cutting the honeycomb molded body 80 in a direction perpendicular to the longitudinal direction. However, the curved line connecting the four vertices is a contracted quadrangle that is curved inward toward the center of gravity of the quadrilateral rather than the straight line connecting the four vertices. If the flow rate of the cooling water flowing through the flowing water pipe 42 of the extrusion molding apparatus 1 according to the first embodiment of the present invention is not sufficient, heat generation due to friction cannot be sufficiently suppressed during extrusion molding. Therefore, the temperature of the kneaded material existing in the peripheral portion of the mold 41 is higher than the temperature of the kneaded material existing in the vicinity of the central portion of the mold 41. Therefore, the moving speed of the kneaded material existing in the peripheral portion is faster than the moving speed of the kneaded material existing in the vicinity of the central portion. As a result, the cross-sectional area of the through-hole in the peripheral portion becomes relatively large, and the contour of the cross section of the honeycomb formed body to be extruded becomes a contracted quadrangle.

As shown in FIG. 4B, in the honeycomb formed body 90 in which the kneaded product is excessively cooled and extruded at a relatively low temperature, the cross-sectional contour of the honeycomb formed body 90 cut in a direction perpendicular to the longitudinal direction. However, the curve that connects the four vertices is a swollen quadrangle that curves outward from the straight line that connects the four vertices. When the flow rate of the cooling water flowing through the flowing water pipe 42 of the extrusion molding apparatus 1 according to the first embodiment of the present invention is excessive, the kneaded product is excessively cooled during the extrusion molding. Therefore, the temperature of the kneaded material existing in the peripheral portion of the mold 41 is lower than the temperature of the kneaded material existing in the vicinity of the central portion of the mold 41. Accordingly, the moving speed of the kneaded material existing in the vicinity of the central portion is faster than the moving speed of the kneaded material existing in the peripheral portion of the mold 41. As a result, the cross-sectional area of the through hole in the vicinity of the central portion is increased, and the cross-sectional contour of the extruded honeycomb formed body is a swollen quadrangle.

The honeycomb formed body 61 becomes a honeycomb fired body 71 by firing at a high temperature, and becomes a honeycomb structure 500 by binding a plurality of honeycomb fired bodies 71. When the honeycomb molded body 61 is deformed, such as the honeycomb molded body 80 having a contracted quadrilateral cross section and the honeycomb molded body 90 having a cross-sectional shape swollen quadrangular, when the honeycomb fired body 71 is bound, It becomes an obstacle. Further, the produced exhaust gas treatment is easily damaged and the exhaust gas purification function is inferior.

Next, the height of the honeycomb formed body 61 measured by the height sensor 51 constituting the extrusion molding apparatus 1 of the present invention will be described.
FIG. 5 (a) shows a height in a direction perpendicular to the extrusion direction of the honeycomb molded body having a cross-sectional shape of a shrinkage quadrangle, which is measured by a height sensor constituting the extrusion molding apparatus according to the first embodiment of the present invention. It is a schematic diagram which shows an example of thickness typically.
FIG. 5B shows a height in a direction perpendicular to the extrusion direction of the honeycomb molded body having a cross-sectional shape of a swelled square, which is measured by a height sensor constituting the extrusion molding apparatus according to the first embodiment of the present invention. It is a schematic diagram which shows an example of thickness typically.

As shown in FIG. 5 (a), the honeycomb molded body 80 whose cross-sectional shape is a contracted quadrangle has a first vertex 81a, a second vertex 81b, a third vertex 81c, and a fourth vertex in the sectional shape. 81d. Further, the first vertex 81a and the second vertex 81b are connected by the first side 82a. The second vertex 81b and the third vertex 81c are connected by the lower side 82b. The third vertex 81c and the fourth vertex 81d are connected by the second side 82c. The first vertex 81a and the fourth vertex 81d are connected by the upper side 82d.

Further, a straight line connecting the first vertex 81a and the fourth vertex 81d is defined as a straight line 83a (a portion indicated by a broken line in FIG. 5A), and a straight line connecting the second vertex 81b and the third vertex 81c. A straight line 83b (a portion indicated by a broken line in FIG. 5A) is used.

The lower side 82 b belongs to the bottom surface of the honeycomb formed body 80 and is a portion in contact with the conveying member 52. Further, the upper side 82d belongs to a surface opposite to the surface to which the lower side 82b belongs. The first side 82a is in contact with the left end of the lower side 82b, and the second side 82c is in contact with the right end of the lower side 82b. FIG. 5A shows one cross section of the honeycomb formed body 80 cut in a direction perpendicular to the longitudinal direction, and the left and right sides are reversed when attention is paid to the other cross section. The positional relationship between 82a and the second side 82c may be reversed, and the left and right sides do not affect the description here, but are handled as described above for convenience.

The first side 82a, the lower side 82b, the second side 82c, and the upper side 82d are each a quadrangle formed by the first vertex 81a, the second vertex 81b, the third vertex 81c, and the fourth vertex 81d. It is curved inward toward the center of gravity of the square rather than the side.

Here, the first vertex 81a, which is the end of the upper side 82d, is defined as the first location, and the distance from the first vertex 81a to the second vertex 81b is defined as the height (h1) at the first location. Further, an intermediate portion of the upper side 82d connecting the first vertex 81a and the fourth vertex 81d is a second location, and the distance from the second location to the straight line 83b is the height (h2) at the second location. And Hereinafter, the height (h2) at the second location will be described in more detail. A midpoint of the straight line 83a is defined as a midpoint 84. A line passing through the midpoint 84 and perpendicular to the straight line 83b is defined as a straight line 85, and an intersection of the straight line 85 and the straight line 83b is defined as a first intersection 86b. The intersection of the upper side 82d and the straight line 85 is defined as a second intersection 86a. The second intersection 86a is an intermediate portion of the upper side 82d, and the height (h2) at the second location is the distance from the first intersection 86b to the second intersection 86a.

As shown in FIG. 5 (b), the honeycomb molded body 90 whose cross-sectional shape is a swelled quadrilateral has a first vertex 91a, a second vertex 91b, a third vertex 91c, and a fourth vertex in the sectional shape. 91d. Further, the first vertex 91a and the second vertex 91b are connected by the first side 92a. The second vertex 91b and the third vertex 91c are connected by a lower side 92b. The third vertex 91c and the fourth vertex 91d are connected by the second side 92c. The first vertex 91a and the fourth vertex 91d are connected by the upper side 92d.

Further, a straight line connecting the first vertex 91a and the fourth vertex 91d is defined as a straight line 93a (a portion indicated by a broken line in FIG. 5B), and a straight line connecting the second vertex 91b and the third vertex 91c. A straight line 93b (a portion indicated by a broken line in FIG. 5B) is used.

The lower side 92 b belongs to the bottom surface of the honeycomb formed body 90 and is a part in contact with the conveying member 52. Further, the upper side 92d belongs to a surface opposite to the surface to which the lower side 92b belongs. The first side 92a is in contact with the left end of the lower side 92b, and the second side 92c is in contact with the right end of the lower side 92b. FIG. 5B shows one cross section of the honeycomb molded body 90 cut in a direction perpendicular to the longitudinal direction, and the left and right sides are reversed when attention is paid to the other cross section. The positional relationship between 92a and the second side 92c may be reversed, and the left and right sides do not affect the description here, but are handled as described above for convenience.

The first side 92a, the lower side 92b, the second side 92c, and the upper side 92d are each a quadrangle formed by the first vertex 91a, the second vertex 91b, the third vertex 91c, and the fourth vertex 91d. It curves outward from the side.

Here, the first vertex 91a, which is the end of the upper side 92d, is defined as the first location, and the distance from the first vertex 91a to the second vertex 91b is defined as the height (h1) at the first location. In addition, an intermediate portion of the upper side 92d connecting the first vertex 91a and the fourth vertex 91d is a second location, and the distance from the second location to the straight line 93b is the height (h2) at the second location. And Hereinafter, the height (h2) at the second location will be described in more detail. The midpoint of the straight line 93a is the midpoint 94. A line passing through the middle point 94 and perpendicular to the straight line 93b is defined as a straight line 95, and an intersection of the straight line 95 and the straight line 93b is defined as a first intersection 96b. The intersection of the upper side 92d and the straight line 95 is defined as a second intersection 96a. The second intersection 96a is an intermediate part of the upper side 92d, and the height (h2) at the second location is the distance from the first intersection 96b to the second intersection 96a.

When the honeycomb formed body 90 is placed on a flat surface, the second side 92b is curved outward, so that the honeycomb formed body 90 is inclined. In such a case, it becomes difficult to measure the height (h1) at the first location and the height (h2) at the second location.
Therefore, it is desirable that a concave portion 54 is provided in a portion of the conveying member 52 that measures the height of a predetermined portion of the honeycomb formed body 90. The recess 54 will be described in detail below.

FIG. 6 schematically shows an example of a cross section of the conveying member of the extrusion molding apparatus according to the first embodiment of the present invention and the honeycomb formed body mounted on the conveying member cut in a direction perpendicular to the conveying direction of the conveying member. It is a perspective view shown.
The width of the recess 54 provided in the transport member 52 is desirably slightly narrower than the distance from the second vertex 91b to the third vertex 91c of the honeycomb formed body 90. The recess 54 is desirably provided continuously along the transport direction of the transport member 52. It is desirable that the depth of the concave portion 54 is such a depth that the surface on which the concave portion 54 is formed does not contact the lower side 92b.
In addition, it is desirable that the honeycomb molded body 90 is placed on the conveying member 52 so that the concave portion 54 is accommodated between the second vertex 91b and the third vertex 91c of the honeycomb molded body 90, and the second vertex Desirably, the honeycomb formed body 90 is placed on the conveying member 52 so that the distance from 91b to the recess 54 is equal to the distance from the third apex 91c to the recess 54.
When the concave portion 54 as described above is provided in the conveying member 52 and the honeycomb molded body 90 is placed as described above, even if the lower side 92b is curved outward, the lower side 92b of the honeycomb molded body 90 is provided. Since the portion formed by the straight line 93b fits in the space formed by the recess 54, the honeycomb formed body 90 is difficult to tilt. Therefore, there is almost no influence on the measurement of the height (h1) at the first location and the height (h2) at the second location.

In the extrusion molding apparatus 1 according to the first embodiment of the present invention, the height sensor 51 determines the shape distortion of the honeycomb molded body manufactured by measuring the height (h1) and the height (h2). Can do.
Note that the height sensor 51 may measure the height (h1) and the height (h2) of the continuous honeycomb formed body 60.

Next, a mechanism in which the extrusion molding apparatus 1 according to the first embodiment of the present invention controls the shape of the honeycomb formed body 61 (continuous honeycomb formed body 60) will be described.

In the extrusion apparatus according to the first embodiment of the present invention, two height sensors are arranged, and one of the height sensors is in the extrusion direction of the honeycomb formed body at the end of the upper side of the substantially square shape. The height (h1) in the vertical direction is measured, and the other height sensor measures the height (h2) in the direction perpendicular to the extrusion direction of the honeycomb formed body in the middle portion of the upper side of the substantially square shape. , The distance difference (D) between the height (h1) and the height (h2) is calculated based on the following formula (1), and the flow rate control mechanism, when the distance difference (D) is 0, When a predetermined flow rate (V ₀ ) is circulated through the cooling water and the distance difference (D) is a positive value, the flow rate of the cooling water is determined based on the absolute value of the distance difference (D). V ₀ ) or more, and when the distance difference (D) is a negative value, the distance difference (D) It is desirable to reduce the flow rate of the cooling water below the above flow rate (V ₀ ) based on the absolute value of.
D = h1-h2 (1)

In the honeycomb formed body 61 manufactured using the extrusion forming apparatus 1 according to the first embodiment of the present invention, the distance difference (D) is −10% with respect to the height (h1) as a result of the following formula (1). Desirably, it is 10%. If the distance difference (D) is within the above range, the honeycomb fired bodies 71 manufactured through the subsequent steps can be suitably assembled, and the manufactured exhaust gas treatment body is hardly damaged and has an exhaust gas purification function. Will also be sufficient.
D = h1-h2 (1)

In order to set the value of the distance difference (D) within the above range, the height sensor 51 measures the height (h1) and the height (h2), and the honeycomb formed body 61 has a sign of shape distortion. It is desirable to control the temperature of the kneaded product.

When the height (h1) and the height (h2) are measured by the height sensor 51 and the value of the distance difference (D) becomes 0 as a result of the above equation (1), the cross-sectional shape of the honeycomb formed body 61 is reduced. Since it shows that almost no distortion has occurred, it means that the temperature of the kneaded product to be extruded is suitable.
A positive value of the distance difference (D) indicates that the cross-sectional shape of the honeycomb formed body 61 is a contracted quadrangle, and therefore the temperature of the kneaded product to be extruded is relatively high. means.
A negative distance difference (D) means that the cross-sectional shape of the honeycomb formed body 61 is a swollen quadrangle, and therefore the temperature of the kneaded product to be extruded is relatively low. To do.

As described above, when shape distortion occurs in the extruded honeycomb formed body 61, when the heights of two different places are measured, the heights are different. Therefore, the height difference measured by the height sensor 51 is different. On the basis of whether the temperature of the kneaded material is high or low, and if the temperature of the kneaded material is high, adjust the control valve built in the flow rate control mechanism 43 to increase the flow rate of the cooling water, When the temperature of the kneaded material is low, the temperature of the kneaded material to be extruded can be kept within a predetermined range by adjusting the control valve built in the flow rate control mechanism 43 to reduce the flow rate of the cooling water. . This mechanism will be described below using a chart.

FIG. 7 is a chart diagram of a mechanism for controlling the temperature of the kneaded product of the extrusion molding apparatus according to the first embodiment of the present invention.
(A) In the extrusion molding apparatus 1 according to the first embodiment of the present invention, the height (h1) and the height (h2) of the extruded honeycomb formed body 61 are measured by the height sensor 51.
(B) The measured height (h1) and height (h2) data is transmitted to the computing device.
(C) The calculation device calculates the distance difference (D) between the height (h1) and the height (h2) by the above equation (1).
(D) The calculation result is sent to the flow rate control mechanism 43.
(E) The flow rate control mechanism 43 performs feedback control for controlling the flow rate of the cooling water based on the value of the distance difference (D) that has been sent. The flow rate control method is as follows.
(E-1) When the distance difference (D) is less than 0 as a result of the calculation, the flow rate control mechanism 43 reduces the flow rate of the cooling water flowing through the flowing water pipe 42 to (V ₀ ) or less, and thus the flow rate control mechanism. The control valve built in 43 is adjusted.
(E-2) As a result of the calculation, when the distance difference (D) exceeds 0, the flow control mechanism 43 increases the flow rate of the cooling water flowing through the flowing water pipe 42 to (V ₀ ) or more. The control valve built in the flow control mechanism 43 is adjusted.

Next, the relationship between the distance difference (D) and the shape distortion of the honeycomb formed body will be described.
In the honeycomb formed body 61, when the temperature difference between the center portion and the peripheral portion is large, the shape distortion of the honeycomb formed body increases.
That is, as the temperature of the peripheral portion becomes relatively higher than the temperature of the central portion, the first side 82a, the lower side 82b, and the second side that form the contracted quadrangle that is the cross-sectional shape of the honeycomb molded body 80 described above. The side edge 82c and the upper edge 82d are sharp curves. In this case, the distance difference (D) is a positive value. As the first side 82a, the lower side 82b, the second side 82c, and the upper side 82d become sharp curves, the absolute value of the distance difference (D) increases.
Further, as the temperature of the central portion becomes relatively higher than the temperature of the peripheral portion, the first side 92a, the lower side 92b, and the second side that form the swollen quadrangle that is the cross-sectional shape of the honeycomb molded body 90 described above. The side 92c and the upper side 92d are sharp curves. In this case, the distance difference (D) is a negative value. As the first side 92a, the lower side 92b, the second side 92c, and the upper side 92d become sharp curves, the absolute value of the distance difference (D) increases.
Therefore, it can be determined how high or low the temperature of the kneaded material is based on the value of the distance difference (D). That is, when the distance difference (D) is a positive value, it means that the larger the absolute value of the distance difference (D) is, the higher the temperature of the peripheral part is than the temperature of the central part, It means that cooling with cooling water is not sufficient. When the distance difference (D) is a negative value, the larger the absolute value of the distance difference (D) means that the temperature of the peripheral portion is relatively lower than the temperature of the central portion, It means that cooling with cooling water is excessive.
Therefore, when the distance difference (D) is 0, the cooling water is circulated a predetermined flow rate (V _0), the flow rate (V ₀₎ as a reference, the distance difference (D) is a positive value In this case, the flow rate of the cooling water is increased to a flow rate (V ₀ ) or more based on the absolute value of the distance difference (D), and when the distance difference (D) is a negative value, the distance difference (D) By reducing the flow rate of the cooling water to a flow rate (V ₀ ) or less based on the absolute value of the kneaded product, the temperature of the kneaded product can be kept within a predetermined range, and the honeycomb molded body 61 is prevented from being deformed. can do.

The relationship between the flow rate of the cooling water and the distance difference (D) will be described in detail.
The flow rate of the cooling water is desirably determined by a function having the distance difference (D) as a variable. The flow rate of the cooling water in this case is expressed as a function V ((D)).
The minimum value of the function V ((D)) is 0. That is, it is a case where cooling water is not circulated. The maximum value of the function V ((D)) is assumed to be V _max . V _max is a flow rate at which the cooling water flows through the flowing water pipe at the maximum, and depends on the thickness of the flowing water pipe.

And a distance difference _{D 1,} to determine the flow rate of the cooling water in some distance difference relationship between _{D 2} is _{D 1 <D 2 ((D} ) ∋D 1, D 2), the extrusion-forming device of the present invention The function V ((D)) is desirably a function that satisfies the relationship V (D ₁ ) ≦ V (D ₂ ).
When the flow rate of the cooling water is determined according to such a function V ((D)), the flow rate of the cooling water increases / decreases as the distance difference (D) increases / decreases. That is, when the value of the distance difference (D) increases, V ((D)) also increases, and when the value of the distance difference (D) decreases, V ((D)) also decreases.
The function V ((D)) that establishes such a relationship will be described below.

FIGS. 8A to 8D are graphs schematically showing an example of a function for determining the flow rate of the cooling water in the extrusion molding apparatus according to the first embodiment of the present invention.
8A to 8D, the vertical axis represents the flow rate of the cooling water, and the horizontal axis represents the value of the distance difference (D).
The function determines the flow rate of the cooling water in the extrusion molding apparatus according to a first embodiment of the present invention V ((D)), but are not limited to, the V _a shown in FIG. _{8 (a) ((D)} ) A linear function such that V _a ((D)) = α (D) + V ₀ (α is an arbitrary coefficient) may be used. When the function V ((D)) is a linear function represented by V _a ((D)) = α (D) + V ₀ (α is an arbitrary coefficient), the coefficient α is the size of the extrusion molding apparatus. It is desirable to determine according to the size of the honeycomb formed body to be manufactured.
Further, V ((D)) may be a function such that the flow rate of the cooling water changes step by step like V _b ((D)) shown in FIG. That is, when D ₁ <(D) ≦ D ₂ (D ₁ and D ₂ are arbitrary numbers), V ((D)) = V ₁ (V ₁ is a constant), and D ₂ <(D) ≦ When D ₃ (D ₃ is an arbitrary number), V ((D)) = V ₂ (V ₂ is a constant larger than V ₁ ), and D _n <(D) ≦ D _{n + 1} (D _n and D _{n + 1} May be a function such that V ((D)) = V _n (V _n is a constant larger than V _n−1 ). The range of the distance difference (D) for determining the flow rate of the cooling water and the flow rate of the cooling water are desirably determined in accordance with the size of the extrusion molding device, the size of the honeycomb formed body to be manufactured, and the like.
Further, V ((D)) is V ((D)) = 0 when (D) ≦ 0 as in V _c ((D)) shown in FIG. 8C, and 0 <( In the case of D), the function may be V ((D)) = V _max . In this case, when the swelling square shape distortion is recognized, the cooling water is not flown, and when the shrinking square shape distortion is recognized, the maximum amount of cooling water is flown.
Further, V ((D)) may be a function that draws an S-shaped curve like V _d ((D)) shown in FIG. In this case, V _d ((D)) is preferably determined in accordance with the size of the extrusion molding device, the size of the honeycomb formed body to be manufactured, and the like.

By controlling the flow rate of the cooling water according to the function V ((D)), it is possible to prevent an unacceptable shape distortion from occurring in the honeycomb formed body 61.

Note that the height of the honeycomb formed body 61 measured by the height sensor 51 is limited to two places: the height (h1) of the vertex 81a (91a) and the height (h2) of the second intersection 86a (96a). It may be a measurement at one place, and may be two places other than the height (h1) of the vertex 81a (91a) and the height (h2) of the second intersection 86a (96a), Three or more measurement points may be used.

When the height of the honeycomb formed body 61 measured by the height sensor 51 is two places other than the height (h1) of the second intersection 86a (96a) and (h2) of the second intersection 86a (96a), The two points may be two arbitrary points on the upper side 82d (92d). In this case, the first location may be a portion other than the second intersection 86a (96a), and the second location may be between the second intersection 86a (96a) and the first location. desirable.
Whether the cross-sectional shape of the honeycomb molded body 61 cut in the direction perpendicular to the longitudinal direction is a contracted quadrangle due to the difference between the height (h1) at the first location and the height (h2) at the second location It can be judged whether it is a swelling square.

When the height of the honeycomb formed body 61 measured by the height sensor 51 is one, it is desirable to measure as follows.
When the temperature of the kneaded material is suitable, shape distortion does not occur in the honeycomb formed body, and the first side 82a (92a), the lower side 82b (92b), the second side 82c (92c), and the upper side 82d (92d) is a substantially straight line. In this case, the height of any part of the upper side 82d (92d) is substantially equal in all parts. Such a height can be obtained in advance. The height of this arbitrary part is defined as (h1 ′).
The height measured by the height sensor 51 is preferably the height of an arbitrary portion of the upper side 82d (92d) excluding the first vertex 81a (91a) and the fourth vertex 81d (91d). The height of this arbitrary portion is (h2 ′). Such height (h2) fluctuates when shape distortion occurs in the honeycomb formed body, and therefore can be used to determine whether or not shape distortion occurs in the honeycomb formed body. The height (h2 ′) is preferably the height of the second intersection 86a (96a) that is most affected by the shape distortion.
Based on the distance difference (D ′) between (h1 ′) and (h2 ′), the cross-sectional shape of the honeycomb formed body 61 cut in the direction perpendicular to the longitudinal direction is calculated by calculating the following equation (2). It can be determined whether it is a contraction quadrangle or a swelling quadrangle. That is, when the distance difference (D ′) is a positive value, the cross-sectional shape of the honeycomb formed body 61 is a contracted quadrangle, and when the distance difference (D ′) is a negative value, the cross section of the honeycomb formed body 61 The shape is a swollen square.
D ′ = h1′−h2 ′ (2)

When the height of the honeycomb formed body 61 measured by the height sensor 51 is three or more, by measuring the height of any three or more points in the fourth side 82d (92d), It can be determined whether the cross-sectional shape of the honeycomb formed body 61 cut in the vertical direction is a contracted quadrangle or a swollen quadrangle.

Further, instead of measuring the height of the honeycomb formed body 61 with the height sensor 51, the width in the direction from the first side 82a (92a) to the second side 82c (92c) may be measured.
When shape distortion has occurred as in the honeycomb formed body 80 (90), the first side 82a (92a) and the second side 82c (92c) are also curved. Therefore, the shape distortion of the honeycomb formed body 61 can be determined by measuring the width of the honeycomb formed body 61. The part for measuring the width of the honeycomb formed body 61 to be measured in this case is not particularly limited, and may be one place or two or more places.

Thus, it is possible to prevent the occurrence of shape distortion in the honeycomb formed body 61 by judging the shape distortion of the honeycomb formed body 61 and feeding back the result to appropriately control the temperature of the kneaded product. it can.
Further, when the temperature of the kneaded product varies depending on the part, the friction between the kneaded product at the low temperature part and the mold 41 becomes larger than the friction between the kneaded product at the high temperature part and the mold 41. Therefore, the portion of the mold 41 that comes into contact with the kneaded product at the low temperature portion is worn out more than the portion of the mold 41 that comes into contact with the kneaded product at the high temperature portion.
However, when the temperature of the kneaded material is appropriately controlled as described above, the difference between the temperature of the kneaded material around the mold 41 and the temperature of the kneaded material near the center portion becomes small. That is, the temperature of the kneaded product is unlikely to vary from part to part. Therefore, since only a part of the mold 41 does not come into contact with the kneaded material having a low temperature, it is possible to suppress an increase in wear of only a part of the mold 41.

Next, a method for producing the honeycomb formed body 61 using the extrusion molding apparatus 1 according to the first embodiment of the present invention will be described.
In the method for producing the honeycomb formed body 61 using the extrusion molding apparatus 1 according to the first embodiment of the present invention, by introducing a raw material made of a wet mixture containing silicon carbide powder from the raw material input port 2, A continuous honeycomb molded body production step for producing a continuous honeycomb molded body 60 in which a large number of through holes are arranged in the longitudinal direction by performing extrusion molding through the mold 41 of the extrusion molded portion 4, and the continuous honeycomb molded body 60. Cutting the substrate into a predetermined length to form a honeycomb formed body 61, and the height sensor 51 measures the height of the honeycomb formed body 61 while the cut honeycomb formed body 61 is conveyed by the conveying member 52. And a flow rate control step of controlling the flow rate of the cooling water by the flow rate control mechanism 43 based on the height of the honeycomb formed body 61 measured by the height sensor 51. The features.

(A) Continuous honeycomb molded body manufacturing step (a-1) Preparation of wet mixture Silicon carbide powder is essential, other ceramic materials, inorganic particles, inorganic fibers, inorganic binders, organic binders, pore formers, plasticizers, lubrication A wet mixture is prepared by mixing an agent, a dispersing agent and the like. Since the blending amount of each component has already been described, it will be omitted.

(A-2) Kneading of wet mixture The wet mixture prepared in the above (a-1) is charged from the raw material inlet 2 of the extrusion molding apparatus 1 according to the first embodiment of the present invention. The wet mixture is pushed into the upper screw mixer 100 by the kneading push roller 102. The wet mixture is kneaded with the kneading screw 110 to obtain a kneaded mixture.
The kneaded material kneaded by the kneading screw 110 is pushed into the die 120 to be in a rod-like or udon noodle state. Further, an upper cutter 140 is provided in the vicinity of the die 120, and the kneaded material in a rod-like or udon noodle state is further finely cut by the upper cutter 140.
The pressure inside the upper stage screw mixer 100 and the inside of the decompression chamber 130 is desirably 50 to 100 kpa lower than the atmospheric pressure (that is, (atmospheric pressure−100 kpa) to (atmospheric pressure−50 kpa)). This is because if the pressure is higher than (atmospheric pressure-50 kPa), bubbles are likely to be caught in the kneaded product, and defects and the like are likely to occur inside the molded body. On the other hand, when the pressure is smaller than (atmospheric pressure−100 kPa), since the vacuum is high, the kneaded product is dried and hardened, so that the moldability is deteriorated.
The kneaded material that has undergone the above steps is taken into the lower screw mixer 200 and kneaded in the same manner as the upper screw mixer 100 to become a kneaded material suitable for extrusion molding.

(A-3) Extrusion Molding The kneaded material that has undergone the above step (a-2) falls to the receiving port 401 of the extrusion screw part 400 and is extruded to the tip part 40 by the extrusion screw 410. When the kneaded material reaches the mold 41, the continuous honeycomb molded body 60 in which a large number of through holes are arranged in the longitudinal direction is extruded.
The time from when the kneaded material enters the upper screw mixer 100 until it is extruded is preferably 50 to 90 minutes. This is because it is necessary to make the entire composition uniform including water and the like by mixing well.

(B) Cutting process The extruded continuous honeycomb molded body 60 is conveyed by the conveying member 52 to a place where the cutting member 53 is disposed. The continuous honeycomb formed body 60 is cut into a predetermined length by the cutting member 53 to form a honeycomb formed body 61.

(C) Height Measurement Step The honeycomb formed body 61 manufactured through the above step (b) is measured by the height sensor 51 for height (h1) and height (h2). Since the height of the honeycomb formed body 61 to be measured is as described above, details are omitted.
The measured height (h1) and height (h2) are transmitted to the computing device.

(D) Flow Control Step In the above calculation device, the distance (D) is obtained by calculating the height (h1) at the first location and the height (h2) at the second location by the following equation (1). The calculation result is transmitted to the cooling water flow rate control mechanism 43.
The flow rate control mechanism 43 controls the flow rate of the cooling water by adjusting the control valve based on the calculation result, and can prevent the shape distortion from occurring in the manufactured honeycomb formed body 61 in advance. Since the relationship between the flow rate of the cooling water and the distance difference (D) is as described above, the details are omitted.
D = h1-h2 (1)

In this step, the cooling water is circulated through the flowing water pipe 42, but the cooling member circulated through the flowing water pipe 42 is not limited to the cooling water, and may be an organic solvent or the like.
The temperature of the cooling water and the like are not particularly limited, but it is desirable to adjust according to the size of the extrusion molding device, the composition of the kneaded product, and the like.

By performing the steps so far, the honeycomb formed body 61 with less shape distortion can be manufactured.

Next, a honeycomb fired body 71 manufactured from the honeycomb formed body 61, a honeycomb structure 500 manufactured using the honeycomb fired body 71, a method for manufacturing the honeycomb fired body 71, and a method for manufacturing the honeycomb structure 500 will be described. To do.

FIG. 9A is a perspective view schematically showing an example of a honeycomb fired body manufactured from a honeycomb formed body manufactured using the extrusion molding apparatus according to the first embodiment of the present invention. FIG. 9B is a cross-sectional view taken along line BB in FIG.
FIG. 10 schematically shows an example of a honeycomb structure manufactured by assembling a plurality of honeycomb fired bodies manufactured from a honeycomb formed body manufactured using the extrusion molding apparatus according to the first embodiment of the present invention. It is a perspective view shown.

The honeycomb formed body 61 becomes a porous honeycomb fired body 71 by being fired through a subsequent process.
As shown in FIG. 9A, the honeycomb fired body 71 has a large number of cells 72 arranged in parallel in the longitudinal direction with the cell walls 73 therebetween, and an outer peripheral wall 74 is formed around the cells 72. One end of the cell 71 is sealed with a sealing material 75.
Accordingly, the exhaust gas G (in FIG. 9B, the exhaust gas is indicated by G and the flow of the exhaust gas is indicated by an arrow in FIG. 9B) always passes through the cell wall 73 that separates the cell 72. After that, the other end face flows out from the other cell 72 opened. When the exhaust gas G passes through the cell wall 73, PM and the like in the exhaust gas are collected. Therefore, the cell wall 73 functions as a filter and can purify the exhaust gas.

The average pore diameter of the pores formed in the honeycomb fired body 71 is preferably 0.5 to 40 μm, and more preferably 20 to 40 μm.
The porosity of the honeycomb fired body 71 is preferably 40 to 70%, and more preferably 60 to 70%.
When the average pore diameter and the porosity are in the above ranges, a large amount of catalyst can be supported on the honeycomb fired body 71.

The aperture ratio formed in the cell wall of the honeycomb fired body 71 is desirably 30 to 60%.
When the aperture ratio is in the above range, PM can be suitably collected.

The thickness of the cell wall 73 of the honeycomb fired body 71 is desirably 0.1 to 0.45 mm, and more desirably 0.1 to 0.3 mm.
When the thickness of the cell wall 73 is within the above range, the cell wall 73 has a certain degree of strength and is not easily damaged by an external impact.

The width of the cells 72 of the honeycomb fired body 71 is preferably 0.2 to 2.0 mm, and more preferably 0.2 to 1.2 mm.
When the width of the cell 72 is in the above range, PM can be suitably collected.

As shown in FIG. 10, the honeycomb structure 500 includes a ceramic block 502 in which a plurality of the honeycomb fired bodies 71 are bonded through an adhesive layer 501, and an outer peripheral coat layer is formed on the outer periphery of the ceramic block 502. 503 is formed. In addition, the outer periphery coating layer 503 should just be formed as needed.

Hereinafter, a method for manufacturing the honeycomb fired body 71 and the honeycomb structure 500 will be described.

(E) Drying process A honeycomb molded body 61 manufactured using the extrusion molding apparatus 1 according to the first embodiment of the present invention is subjected to a microwave dryer, a hot air dryer, a dielectric dryer, a vacuum dryer, and a vacuum dryer. Dry using a freeze dryer or the like.

(F) Sealing step Next, if necessary, a predetermined amount of a sealing material paste serving as a sealing material is filled so that either one end of the cells of the honeycomb formed body 61 is sealed. 62 is sealed. Note that sealing of the cells may be performed after the honeycomb structure 500 is manufactured.

If shape distortion occurs in the honeycomb formed body 61, gaps are likely to occur when the plug material paste is filled. When such a gap is generated, PM leaks through the gap when the exhaust gas flows into the honeycomb fired body 71 manufactured through the subsequent process. Therefore, the PM collection function of the honeycomb fired body 71 is impaired.

The constituent material of the sealing material paste is not particularly limited as long as the cells 62 can be sealed, but may be the same as the constituent material of the kneaded material, for example.

The viscosity of the sealing material paste is desirably 20 to 50 PaS.

Filling of the plug material paste may be performed as necessary. When the plug material paste is filled, for example, the honeycomb structure obtained through the post-process can be suitably used as a ceramic filter. In the case where the sealing material paste is not filled, for example, a honeycomb structure obtained through a subsequent process can be suitably used as a catalyst carrier.

(G) Degreasing step Next, the honeycomb degreased body is manufactured by degreasing the honeycomb formed body 61 in which the cells are sealed. The degreasing treatment is performed by heating at 300 to 650 ° C. in an oxygen-containing atmosphere. By performing the degreasing treatment, most of the organic binder in the honeycomb formed body 61 is volatilized and decomposed and disappeared.

(H) Firing step Next, the honeycomb degreased body is heated to 1700 to 2000 ° C. in an inert gas atmosphere such as nitrogen or argon, and fired, whereby a plurality of cells 72 penetrating the porous longitudinal direction are obtained. A honeycomb fired body 71 can be obtained in which the cell walls 73 are arranged side by side and any one end of the cells 72 is sealed.

In the above (g) degreasing step and (h) firing step, it is desirable to mount the honeycomb formed body 61 on a predetermined firing jig that covers the entire honeycomb formed body 61, and to degrease and fire. When the firing jig is used, the degreasing step and the firing step can be efficiently performed, and the honeycomb formed body 61 can be prevented from being damaged during replacement.

(I) Honeycomb fired body assembly manufacturing step Next, a sealing material paste layer to be the adhesive material layer 501 is applied to the side surface of the honeycomb fired body 71 with a uniform thickness to form a sealing material paste layer. The process of sequentially laminating the other honeycomb fired bodies 71 on the material paste layer is repeated to produce an aggregate of honeycomb fired bodies 71 having a predetermined size.
In this step, after assembling a required number of honeycomb fired bodies through the gap holding material, the gaps between the honeycomb fired bodies may be filled in a lump with the sealing material paste.
Thereafter, the aggregate of the honeycomb fired bodies 71 is heated to dry and solidify the sealing material paste layer to form an adhesive layer 501.

When manufacturing the aggregate of the honeycomb fired bodies 71, if the honeycomb fired body 71 has a shape distortion, a gap is easily formed between the aggregates. In addition, when the honeycomb fired body 71 is deformed in shape, the stress applied to the strained portion is increased, and the aggregate of the honeycomb fired body 71 is easily damaged.

As said sealing material paste, what consists of an inorganic binder, an organic binder, an inorganic fiber, and / or an inorganic particle etc. are mentioned, for example.

Examples of the inorganic binder include silica sol and alumina sol. These may be used alone or in combination of two or more. Among the inorganic binders, silica sol is desirable.

Examples of the organic binder include polyvinyl alcohol, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, and the like. These may be used alone or in combination of two or more. Among the organic binders, carboxymethyl cellulose is desirable.

Examples of the inorganic fibers include ceramic fibers such as silica-alumina, mullite, alumina, and silica. These may be used alone or in combination of two or more. Among the inorganic fibers, alumina fibers are desirable.

Examples of the inorganic particles include carbides and nitrides, and inorganic powders made of silicon carbide, silicon nitride, and boron nitride are preferable. These may be used alone or in combination of two or more. Among the inorganic particles, silicon carbide having excellent thermal conductivity is desirable.

Furthermore, a pore-forming material such as balloons that are fine hollow spheres containing oxide-based ceramics, spherical acrylic particles, and graphite may be added to the sealing material paste as necessary.
The balloon is not particularly limited, and examples thereof include an alumina balloon, a glass micro balloon, a shirasu balloon, a fly ash balloon (FA balloon), and a mullite balloon. Of these, alumina balloons are desirable.

(J) Cutting Step Next, using a diamond cutter or the like, the aggregate of the honeycomb fired bodies 71 to which a plurality of honeycomb fired bodies 71 are bonded through the adhesive layer 501 is subjected to a cutting process, and the cylindrical ceramic block 502 is cut. Is made.
The shape of the ceramic block 502 manufactured by this manufacturing method is not limited to a cylindrical shape, and may be other column shapes such as an elliptical column shape.
Then, the outer peripheral coat layer 503 is formed on the outer periphery of the honeycomb block 502 using the sealing material paste. By passing through such a process, the honeycomb structure 500 in which the outer peripheral coat layer 503 is provided on the outer peripheral portion of the cylindrical ceramic block 502 in which a plurality of the honeycomb fired bodies 71 are bonded via the adhesive layer 501 is manufactured. can do.

Further, when manufacturing the honeycomb structure, a catalyst may be supported on the honeycomb structure 500 as necessary.
The catalyst may be supported on the honeycomb fired body 71 before the assembly is produced.
When the catalyst is supported, it is desirable to form an alumina film having a high specific surface area on the surface of the honeycomb structure, and to apply a promoter such as platinum and a catalyst such as platinum to the surface of the alumina film.

As a method of forming an alumina film on the surface of the honeycomb structure 500, for example, a method of impregnating the honeycomb structure 500 with a solution of a metal compound containing aluminum such as Al (NO ₃ ) ₃ and heating, an alumina powder And a method of heating the honeycomb structure by impregnating the honeycomb structure with the solution.
Examples of a method for applying a promoter to the alumina film include a method in which a honeycomb structure is impregnated with a solution of a metal compound containing a rare earth element such as Ce (NO ₃ ) ₃ and heated. .

As a method for imparting a catalyst to the alumina membrane, for example, a dinitrodiammine platinum nitrate solution ([Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] HNO ₃ , platinum concentration 4.53% by weight) or the like is used. A method of impregnating and heating is used.
Alternatively, the catalyst may be applied by a method in which a catalyst is applied to alumina particles in advance and the honeycomb structure 500 is impregnated with a solution containing the alumina powder to which the catalyst is applied and heated.

In FIG. 10, the honeycomb structure 500 is formed by combining 16 honeycomb fired bodies 71. However, the number of honeycomb fired bodies 71 is not particularly limited, and may be more or less than 16. .

In FIG. 10, the honeycomb structure 500 has a cylindrical shape, but may have an arbitrary shape such as an elliptical column shape or a rectangular column shape.

Hereinafter, the operational effects of the extrusion molding apparatus according to the first embodiment of the present invention and the method for manufacturing a honeycomb formed body using the extrusion molding apparatus according to the first embodiment of the present invention will be described.

(1) According to the extrusion molding apparatus according to the first embodiment of the present invention, at the front end of the extrusion molding unit, the flowing water pipe for allowing the cooling water to pass therethrough and the flow rate of the cooling water are controlled. A flow rate control mechanism is disposed, and at least one height sensor for measuring a height in a direction perpendicular to the extrusion direction of the manufactured honeycomb formed body is disposed in the transport unit of the extrusion molding apparatus. Since the flow rate of the cooling water is controlled by the flow rate control mechanism based on the height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the sensor, the temperature of the kneaded material passing through the mold is kept within a predetermined range. It is possible to prevent shape distortion from occurring in the manufactured honeycomb formed body.
(2) According to the method for manufacturing a honeycomb formed body using the extrusion molding apparatus according to the first embodiment of the present invention, the height in the direction perpendicular to the extrusion direction of the honeycomb formed body measured by the height sensor is set. Based on this, the flow rate of the cooling water is controlled by the flow rate control mechanism, so that the temperature of the kneaded material passing through the mold can be maintained within a predetermined range, and shape distortion is prevented from occurring in the manufactured honeycomb formed body. be able to.

Example 1
(A) Continuous honeycomb molded body preparation step (a-1) Preparation of wet mixture Silicon carbide powder 16 having an average particle diameter of 0.05 to 1.0 μm and silicon carbide powder 16 having an average particle diameter of 0.05 to 1.0 μm. 2% by weight, acrylic resin (trade name “NS-P20”) 19.2% by weight as a pore former, methyl cellulose (trade name “65SH-15000”) 4.0% by weight as an organic binder, plasticizer As a lubricant, 1.3% by weight of glycerin, 2.4% by weight of polyoxypropylene alkyl ether as a lubricant, and 19.1% by weight of ion-exchanged water were mixed and mixed in a mixer to prepare a wet mixture.

(A-2) Kneading of wet mixture The wet mixture prepared in the above (a-1) was introduced from the raw material charging port of the extrusion molding apparatus, and a kneaded product was prepared by an upper screw mixer and a lower screw mixer.
At this time, the internal pressure of each screw mixer was made 65 kPa lower than the atmospheric pressure.

(A-3) Extrusion Molding The kneaded product that has undergone the above step (a-2) fell to the receiving port of the extrusion screw part and was extruded to the tip part by the extrusion screw.
A die for forming a honeycomb molded body having a cell width of 1.20 mm and a cell wall thickness of 0.28 is attached to the tip portion, and the kneaded product is extruded and extruded from the die by an extrusion screw. Thus, a continuous honeycomb molded body in which a large number of through holes were arranged in the longitudinal direction was produced.
Further, the height in the direction perpendicular to the extrusion direction of the extruded continuous honeycomb molded body was 35.0 mm.

(B) Cutting step The extruded continuous honeycomb molded body was transported to a place where the cutting member was disposed by a transporting member composed of a rotating roller disposed in the transporting section, and was cut to a length of 200 mm. . The continuous honeycomb formed body after cutting becomes a honeycomb formed body.

(C) Height measurement process Two units arranged on the conveying member with the height (h1) and the height (h2) in the direction perpendicular to the extrusion direction of the honeycomb formed body produced through the step (b) The laser displacement sensor (trade name “ZX2” manufactured by OMRON Corporation) was used.
Since each honeycomb molded body conveyed by the conveying member passes through substantially the same place each time, the laser displacement sensor for measuring the height (h1) has a cross-sectional shape perpendicular to the longitudinal direction of the honeycomb molded body and has a substantially rectangular upper side. Pre-fixed on the place where the end passes. Similarly, the laser displacement sensor for measuring the height (h2) was fixed in advance on the place where the middle part of the upper side of the substantially quadrilateral passes.

(D) The flow rate control process computer calculates the distance (D) by calculating the following formula (1) for the height (h1) and the height (h2), and the result is transmitted to the flow rate control mechanism. It was done.
When the distance difference (D) becomes -3 mm or less, the flow rate control mechanism causes the coolant to flow through the piping for running water arranged around the mold and the casing. The valve was controlled to be open. The amount of flowing water at this time was 15 m ³ / min, and the temperature of the cooling water was 20 ° C.
Further, when the distance difference (D) becomes 3 mm or more, the control valve is closed in order to stop the flow of the cooling water to the running water pipe arranged around the mold. Controlled.
D = h1-h2 (1)

(E) Drying process The moisture was removed from the honeycomb formed body manufactured through the above process using a dryer using both microwave and hot air.

(F) Sealing process The honeycomb molded body after drying is cut so as to have a total length of 150 mm, and the sealing material paste is applied to predetermined cells of the honeycomb molded body using a sealing material paste having the same composition as the wet mixture. Was sealed to seal the cell.
Thereafter, the honeycomb formed body in which the cells were sealed was heated to 80 to 130 ° C. with a hot air dryer to dry the sealing material paste.

(G) Degreasing process The honeycomb molded body in which the cells were sealed was heated at 400 ° C for 2 hours in an atmosphere containing 10% oxygen to obtain a honeycomb degreased body.

(H) Firing step The honeycomb degreased body obtained through the step (g) was fired by heating at 2000 ° C for 2 hours in a nitrogen atmosphere to obtain a honeycomb fired body.

A total of 20 honeycomb fired bodies were produced by the above process.

(Comparative Example 1)
(D) Opening and closing of the control valve in the flow rate control step is performed based on the degree of deformation of the honeycomb molded body by visual observation instead of performing based on the height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the laser displacement sensor. A honeycomb fired body was produced in the same manner as in Example 1 except that the above was performed. That is, when the shape of the end face of the honeycomb formed body is visually determined to be a contracted quadrangle, cooling water is circulated, and when the shape of the end face of the honeycomb formed body is determined to be a swollen quadrilateral, the flow of cooling water is stopped. .

(Evaluation of shape distortion)
Of the 20 honeycomb fired bodies produced in Example 1 and Comparative Example 1, 5 were randomly extracted, and the presence or absence of shape distortion of the honeycomb fired bodies was visually confirmed. There are the following three evaluation methods.
(Evaluation 1) Deformation of end face shape of honeycomb fired body When the end face of the honeycomb fired body is visually observed and shape distortion (swelling quadrangle, contraction quadrangle, etc.) is recognized in the honeycomb fired body, "the end face shape is deformed" did.
(Evaluation 2) Gaps generated in the sealing material filled in the cells of the honeycomb fired body When the cells filled with the sealing material of the honeycomb fired body were visually observed, "
(Evaluation 3) Amount of Deviation in Height of Honeycomb Fired Body A case where the absolute value of the distance difference (D) of the honeycomb fired body was larger by 5 mm or more was defined as “height deviation”.
These results are shown in Table 1 below.

As shown in Table 1, Example 1 was good in all evaluations.
On the other hand, in Comparative Example 1, in Evaluation 1, two of the five honeycomb fired bodies were evaluated as “with end face shape deformation”. In evaluation 2, two of the five honeycomb fired bodies were evaluated as having “filling gaps”. In Evaluation 3, it was evaluated that “there was a height shift” in two of the five honeycomb fired bodies.

(Second embodiment)
Hereinafter, a second embodiment that is an embodiment of the extrusion molding apparatus and the method for manufacturing a honeycomb molded body of the present invention will be described.

The extrusion molding apparatus according to the second embodiment of the present invention is the same as the extrusion molding apparatus according to the first embodiment of the present invention except that the control method of the flow rate of the cooling water is different.

In the extrusion apparatus according to the second embodiment of the present invention, the distance difference (D) between the height (h1) at the first location and the height (h2) at the second location, and the distance per unit time. The flow rate of the cooling water is controlled based on the change amount of the difference (D).
Since the height (h1) at the first location, the height (h2) and the distance difference (D) at the second location have already been described, details are omitted.

A method for controlling the flow rate of the cooling water in the extrusion molding apparatus according to the second embodiment of the present invention will be described in detail.
In the extrusion molding apparatus according to the second embodiment of the present invention, the height sensor calculates the height (h1) and the height (h2) in the direction perpendicular to the extrusion direction of the honeycomb molded body at the first time (t1). , And at a second time (t2) after a predetermined time has elapsed from the first time.
The distance difference between the height (h1) and the height (h2) measured by the height sensor at the first time (t1) is defined as (D _t1 ), and is measured by the sensor at the second time (t2). The distance difference between the heights (h1) and (h2) is defined as (D _t2 ).
The flow rate per unit time of the cooling water flowing from the first time (t1) to the second time (t2) is defined as a flow rate ( _Vt1-t2 ).
Flow control mechanism in the second embodiment of the present invention, the distance difference between the second time than the distance difference between the first time (D _t1) (D _t2) is large and, in the second time When the distance difference (D _t2 ) is a positive value, the flow rate per unit time of the cooling water is increased more than the flow rate (V _{t1 -t2} ), and is greater than the distance difference (D _t1 ) at the first time. When the distance difference (D _t2 ) at the second time is small and the distance difference (D _t2 ) at the second time is a negative value, the flow rate of cooling water per unit time is set to the flow rate (V _{t1 -T2} ) is reduced.

That is, in the extrusion molding apparatus according to the second embodiment of the present invention, the opening / closing angle of the control valve built in the flow control mechanism is adjusted based on the distance difference (D) and the amount of change in the distance difference D per unit time. By doing so, it is possible to control the flow rate of the cooling water and prevent the occurrence of shape distortion in the manufactured honeycomb formed body.

The change with time of the distance difference (D) in the honeycomb formed body produced by the extrusion molding apparatus according to the second embodiment of the present invention will be described.

When the flow rate of the cooling water is constant, the shape distortion of the extruded honeycomb formed body proceeds with time.
Therefore, the distance difference (D _t1 ) in the honeycomb molded body at the first time, and the distance difference (D _t2 ) in the honeycomb molded body at the second time after a predetermined time has elapsed from the first time. It is possible to determine whether the temperature of the kneaded product is relatively high or low.
That is, the distance difference between the second time than the distance difference between the first time (D _t1) (D _t2) is large means that the temperature of the kneaded material is becoming relatively high, A smaller distance difference (D _t2 ) at the second time than a distance difference (D _t1 ) at the first time means that the temperature of the kneaded material is becoming relatively lower.

As described above, the relationship among the distance difference (D _t1 ), the distance difference (D _t2 ), and the (D) change amount per unit time is as follows.
Distance difference in distance difference (D _t1) the second time than at the first time (D _t2) is large and, if the distance difference between the second time (D _t2) is a positive value Means that the shape distortion of the shrinking rectangle is progressing.
Distance difference in distance difference (D _t1) the second time than at the first time (D _t2) is small and, if the distance difference between the second time (D _t2) is a positive value Means that the shape distortion of the contraction rectangle is being eliminated.
Distance difference in distance difference (D _t1) the second time than at the first time (D _t2) is small and, if the distance difference between the second time (D _t2) is a negative value Means that the shape distortion of the swollen square is progressing.
Distance difference in distance difference (D _t1) the second time than at the first time (D _t2) is large and, if the distance difference between the second time (D _t2) is a negative value Means that the shape distortion of the swollen square is being resolved.
This will be described in detail below using graphs.

FIG. 11 is a graph schematically showing an example of a change with time of the distance difference (D) in a honeycomb formed body manufactured using the extrusion molding apparatus according to the second embodiment of the present invention.
In the graph shown in FIG. 11, the vertical axis indicates the distance difference (D) in the honeycomb formed body, and the horizontal axis indicates time (t).

In the process of extruding the honeycomb formed body, the temperature of the kneaded product increases with time due to friction. Therefore, the cross-sectional shape of the honeycomb formed body becomes a contracted quadrangle, and the shape distortion increases with time. Therefore, the distance difference (D) in the honeycomb formed body increases with time. In other words, the shape distortion of the contraction rectangle is in progress. In such a state, the distance difference (D) is a positive value.

The shape distortion in which the cross section of the honeycomb formed body is a contracting quadrangle can be eliminated by lowering the temperature of the kneaded product.
In order to quickly lower the temperature of the kneaded material, the flow rate per unit time of the cooling water is set to the flow rate per unit time of the cooling water flowing between the first time and the second time (t2) (V It is desirable to increase it more than _t1-t2 ). When the flow rate of the cooling water is controlled in this way, cooling with the cooling water is superior to heat generation due to friction. Therefore, the temperature rise of the kneaded product stops. When the temperature rise of the kneaded product stops, the distance difference (D) in the honeycomb formed body stops increasing. The time at this time is t _a.

Furthermore, if cooling with cooling water is superior to heat generation due to friction, the temperature of the kneaded material will drop over time. For this reason, the shape distortion in which the cross-sectional shape of the honeycomb formed body is a contracting quadrangle is eliminated with time. Therefore, the distance difference (D) in the honeycomb formed body approaches 0 over time. In such a state, the distance difference (D) is a positive value.
If such a state is continuously maintained, the distance difference (D) in the honeycomb formed body becomes zero. The time at this time is t _b.

If the state where the cooling with the cooling water is superior to the heat generated by the friction is maintained, the kneaded material is excessively cooled. Therefore, the cross-sectional shape of the honeycomb formed body becomes a swollen square, and the shape distortion increases with time. Therefore, the distance difference (D) in the honeycomb formed body becomes smaller with time. That is, the shape distortion of the swollen square is in progress. In such a state, the distance difference (D) is a negative value.

The shape distortion in which the cross section of the honeycomb formed body is a contracting quadrangle can be eliminated by increasing the temperature of the kneaded material.
In order to quickly raise the temperature of the kneaded product, it is desirable to reduce the flow rate per unit time of the cooling water rather than the flow rate (V _{t1 -t2} ). When the flow rate of the cooling water is controlled in this way, heat generated by friction is superior to cooling by the cooling water. Therefore, the temperature drop of the kneaded product stops. When the decrease in the temperature of the kneaded product stops, the distance difference (D) in the honeycomb formed body stops decreasing. This time is t _c .

Further, if the heat generated by friction is superior to the cooling by the cooling water, the temperature of the kneaded product will rise with time. Therefore, the shape distortion in which the cross-sectional shape of the honeycomb formed body is a swollen quadrangle is eliminated with time. Therefore, the distance difference (D) in the honeycomb formed body approaches 0 over time. In such a state, the distance difference (D) is a negative value.
If such a state is continuously maintained, the distance difference (D) in the honeycomb formed body becomes zero. The time at this time is t _d.

Heat generation due to friction, and if a state of over than cooling by the cooling water continues to be maintained, the temperature of the kneaded material, as well as the temperature of the kneaded product from the time 0 to t _a will over time increases. Therefore, similarly to the flow control of the cooling water from time 0 to t _a, it is desirable to control the flow rate of the cooling water.

In the extrusion molding apparatus according to the second embodiment of the present invention, the flow rate of the cooling water is desirably controlled in the same manner.

When the distance difference in the honeycomb molded body at time t is expressed by a function D (t), the amount of change in the distance difference (D) is a value obtained by differentiating D (t) by t. Let this change amount be D ′ (t).
In FIG. 11, when t = 0, D (0) = 0. In such a case, it means that shape distortion does not occur in the honeycomb formed body.
11, the case of _{0 <t <t a, 0} <D (t) becomes 0 becomes <D'(t). In such a case, it means that the shape distortion of the contraction rectangle is progressing.
For t = _{t a} in FIG. 11, the _D'(t a) = 0 it becomes extreme values.
In FIG. 11, when t _a <t <t _b , 0 <D (t) and D ′ (t) <0. In such a case, it means that the shape distortion of the contraction rectangle is being eliminated.
11, the case of t = _{t b,} the D _(t b) = 0. In such a case, it means that shape distortion does not occur in the honeycomb formed body.
In FIG. 11, when t _b <t <t _c , D (t) <0 and D ′ (t) <0. In such a case, it means that the shape distortion of the swollen square is progressing.
In FIG. 11, when t = t _c , D (t _c ) = 0. In such a case, it means that shape distortion does not occur in the honeycomb formed body.
In FIG. 11, when t _c <t <t _d , D (t) <0 and 0 <D ′ (t). In such a case, it means that the shape distortion of the swollen square is being eliminated.
11, the case of t = _{t d,} the _D'(t d) <0. In such a case, it means that shape distortion does not occur in the honeycomb formed body.

In the extrusion molding apparatus according to the second embodiment of the present invention, when 0 <D (t) and 0 <D ′ (t), it means that the shape distortion of the shrinking quadrilateral is progressing. It is desirable to increase the flow rate. In addition, when D (t) <0 and D ′ (t) <0, it means that the shape distortion of the swollen square is progressing, so it is desirable to reduce the flow rate of the cooling water.

In the extrusion molding apparatus according to the second embodiment of the present invention, it is desirable to control the flow rate of the cooling water so that the difference between D (t _a ) and D (t _c ) is small.
As a method of controlling the flow rate of the cooling water so as to reduce the difference between D (t _a ) and D (t _c ), the predetermined time between the first time and the second time is shortened. Etc.

The method for manufacturing a honeycomb formed body according to the second embodiment of the present invention is different from the method for manufacturing the honeycomb formed body according to the first embodiment of the present invention except that the method for controlling the flow rate of the cooling water is different in the flow rate control step. The same.
Since the measurement of the height in the direction perpendicular to the extrusion direction of the honeycomb formed body and the method for controlling the flow rate of the cooling water have already been described in the description of the extrusion apparatus according to the second embodiment of the present invention. Details are omitted.

The extrusion molding apparatus according to the second embodiment of the present invention and the method for manufacturing a honeycomb formed body using the extrusion molding apparatus according to the second embodiment of the present invention are described in the first embodiment of the present invention (1 ) And (2).

(Third embodiment)
Hereinafter, a third embodiment which is an embodiment of the extrusion molding apparatus and the method for manufacturing a honeycomb molded body of the present invention will be described.

The extrusion molding apparatus according to the third embodiment of the present invention has a single vertical height with respect to the extrusion direction of the honeycomb molded body measured by the height sensor, and a method for controlling the flow rate of the cooling water. Except for the difference, this is the same as the extrusion molding apparatus according to the second embodiment of the present invention.

The control method of the flow rate of the cooling water in the extrusion molding apparatus according to the third embodiment of the present invention will be described in detail.
In the extrusion molding apparatus according to the third embodiment of the present invention, the shape of the cross section perpendicular to the longitudinal direction of the honeycomb molded body is a substantially rectangular shape, and the height sensor The height is measured at a first time (t1) and a second time (t2) after a predetermined time has elapsed from the first time, and the height is measured at the first time (t1). The height of the predetermined portion of the honeycomb molded body measured by the sensor is defined as the height (H _t1 ) at the first time, and the honeycomb molding measured by the height sensor at the second time (t2). The height of the predetermined part of the body is defined as the height (H _t2 ) at the second time.
The height of a predetermined portion of the honeycomb formed body in the case where each side constituting the substantially rectangular shape is a straight line is defined as a height (H _b ).
Assuming that the flow rate per unit time of the cooling water flowing from the first time (t1) to the second time (t2) is a flow rate ( _Vt1-t2 ), the flow rate control mechanism is The height (H _t1 ) at the second time is higher than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is the height (H _b ). Is lower than the flow rate (V _t1-t2 ) after the measurement of the height (H _t2 ) at the second time, the flow rate per unit time is increased to the first time. The height (H _t1 ) at the second time is lower than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is higher than the height (H _b ). If, after the measurement of the height of the second time (H _t2), than the flow rate per unit of the cooling water times the flow rate (V _t1-t2) Shape distortion in the honeycomb molded body by decreasing can be prevented from occurring.

That is, in the extrusion molding apparatus according to the third embodiment of the present invention, the height of a predetermined portion of the honeycomb molded body is measured over time, and a control valve with a built-in control function in the flow rate control mechanism based on the amount of change. By adjusting the opening / closing angle, it is possible to control the flow rate of the cooling water and prevent shape distortion from occurring in the manufactured honeycomb formed body.
The flow rate of the cooling water is preferably controlled immediately after measuring the height of a predetermined portion of the honeycomb formed body at the second time.

The height of the predetermined portion of the honeycomb molded body measured by the extrusion molding apparatus according to the third embodiment of the present invention is the first height of the honeycomb molded body 80 (90) shown in FIG. 5 (a) or (b). The distance from any one of the fourth sides 82d (92d) excluding the vertex 81a (91a) and the fourth vertex 81d (91d) to the straight line 83b (93b) is preferably the first intersection point More preferably, the distance is from 86b (96b) to the second intersection 86a (96a).

A change with time in the height of a predetermined portion of the honeycomb formed body manufactured by the extrusion molding apparatus according to the third embodiment of the present invention will be described.

The cross section perpendicular to the longitudinal direction of the honeycomb formed body is substantially a quadrangle, but when shape distortion occurs, it becomes a contracted quadrangle or a swollen quadrangle.
Further, the state in which the four sides are substantially straight is a state in which no shape distortion occurs in the honeycomb formed body. The height of a predetermined portion of the honeycomb molded body in a state where no shape distortion is generated in the honeycomb molded body is defined as a predetermined height (H _b ).
When the temperature of the wet mixture is relatively high, the temperature of the central portion is likely to be lower than the temperature of the peripheral portion, and the peripheral portion is likely to move, so that the cross-sectional area of the through hole in the peripheral portion becomes relatively large. As a result, the above-described contraction rectangle is obtained. That is, when the temperature of the wet mixture is relatively high, the curve forming the shrinkage quadrangle is bent inward, so that the height of the predetermined portion of the honeycomb formed body is higher than the predetermined height (H _b ). Will also be lower.
When the temperature of the wet mixture is relatively low, the temperature of the central portion where the temperature is difficult to decrease is relatively higher than the temperature of the peripheral portion, and the vicinity of the central portion is easily moved. For this reason, the cross-sectional area of the through-hole in the vicinity of the central portion is increased, and as a result, the above-described swelling quadrangle is obtained. That is, when the temperature of the wet mixture is relatively low, the curve forming the swollen square is bent outward, so that the height of the predetermined portion of the honeycomb formed body is higher than the predetermined height (H _b ). Also gets higher.

Further, when the flow rate of the cooling water is constant, the shape distortion of the extruded honeycomb formed body proceeds with time.
Therefore, the height (H _t1 ) of the predetermined portion of the honeycomb formed body at the first time and the height of the predetermined portion of the honeycomb formed body at the second time after a predetermined time has elapsed from the first time. By measuring the _thickness (H _t2 ), it can be determined whether the temperature of the wet mixture is becoming relatively high or low.
That is, the height at the first time (H _t1 ) is higher than the height at the second time (H _t2 ) means that the temperature of the wet mixture is becoming relatively high, That the height (H _t1 ) at the first time is lower than the height (H _t2 ) at the second time means that the temperature of the wet mixture is becoming relatively low.

From the above, the relationship between (H _b ), (H _t1 ), and (H _t2 ) is as follows.
The height (H _t1 ) at the first time is higher than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is a predetermined height (H _b If it is lower than), it means that the shape distortion of the shrinking quadrangle is progressing.
The height (H _t1 ) at the first time is lower than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is a predetermined height (H _b Lower than) means that the shape distortion of the shrinking rectangle is being eliminated.
The height (H _t1 ) at the first time is lower than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is a predetermined height (H _b Higher than) means that the shape distortion of the swollen square is progressing.
The height (H _t1 ) at the first time is higher than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is a predetermined height (H _b Higher than) means that the shape distortion of the swollen square is being resolved.

FIG. 12 is a graph schematically showing an example of a change in height of a predetermined portion of the honeycomb formed body manufactured using the extrusion molding apparatus according to the third embodiment of the present invention with time.
In the graph shown in FIG. 12, the vertical axis indicates the height of a predetermined portion of the honeycomb formed body, and the horizontal axis indicates time (t).

In the process in which the honeycomb formed body is extruded, the temperature of the wet mixture increases with time due to friction. Therefore, the cross-sectional shape of the honeycomb formed body becomes a contracted quadrangle, and the shape distortion increases with time. Therefore, the height of the predetermined portion of the honeycomb formed body becomes lower than _Hb with time. In other words, the shape distortion of the contraction rectangle is in progress. In such a state, the height (H _t1 ) at the first time is higher than the height (H _t2 ) at the second time.

The shape distortion in which the cross section of the honeycomb formed body is a contracting quadrangle can be eliminated by lowering the temperature of the wet mixture.
In order to quickly lower the temperature of the wet mixture, the flow rate per unit time of the cooling water is set to the flow rate per unit time (V) of the cooling water flowing between the first time and the second time (t2). It is desirable to increase it more than _t1-t2 ). When the flow rate of the cooling water is controlled in this way, cooling with the cooling water is superior to heat generation due to friction. Therefore, the temperature rise of the wet mixture stops. When the increase in the temperature of the wet mixture stops, the height of the predetermined portion of the honeycomb formed body stops decreasing. The time at this time is t _a.

Furthermore, if cooling with cooling water is superior to heat generation due to friction, the temperature of the wet mixture decreases with time. For this reason, the shape distortion in which the cross-sectional shape of the honeycomb formed body is a contracting quadrangle is eliminated with time. Accordingly, the height of the predetermined portion of the honeycomb formed body approaches _Hb with time. In such a state, the height (H _t1 ) at the first time is lower than the height (H _t2 ) at the second time.
If such a state is continuously maintained, the height of the predetermined portion of the honeycomb formed body becomes _Hb . The time at this time is t _b.

If the state where the cooling with the cooling water is superior to the heat generated by the friction is maintained, the wet mixture is excessively cooled. Therefore, the cross-sectional shape of the honeycomb formed body becomes a swollen square, and the shape distortion increases with time. Therefore, the height of the predetermined portion of the honeycomb formed body becomes higher with time than _Hb . That is, the shape distortion of the swollen square is in progress. In such a state, the height (H _t1 ) at the first time is lower than the height (H _t2 ) at the second time.

The shape distortion in which the cross section of the honeycomb formed body is a contracting quadrangle can be eliminated by increasing the temperature of the wet mixture.
In order to quickly increase the temperature of the wet mixture, it is desirable to reduce the flow rate of cooling water per unit time rather than the flow rate (V _{t1 -t2} ). When the flow rate of the cooling water is controlled in this way, heat generated by friction is superior to cooling by the cooling water. This stops the temperature drop of the wet mixture. When the temperature drop of the wet mixture stops, the height of the predetermined portion of the honeycomb formed body stops increasing. This time is t _c .

Further, if the heat generated by friction is superior to the cooling by the cooling water, the temperature of the wet mixture will increase with time. Therefore, the shape distortion in which the cross-sectional shape of the honeycomb formed body is a swollen quadrangle is eliminated with time. Accordingly, the height of the predetermined portion of the honeycomb formed body approaches _Hb with time. In such a state, the height (H _t1 ) at the first time is higher than the height (H _t2 ) at the second time.
If such a state is continuously maintained, the height of the predetermined portion of the honeycomb formed body becomes _Hb . The time at this time is t _d.

Heat generation due to friction, and if a state of over than cooling by the cooling water continues to be maintained, the temperature of the wet mixture, as well as the temperature of the wet mixture to the time 0 to t _a will over time increases. Therefore, similarly to the flow control of the cooling water from time 0 to t _a, it is desirable to control the flow rate of the cooling water.

In the extrusion molding apparatus according to the third embodiment of the present invention, the flow rate of the cooling water is desirably controlled in the same manner.

When the height of a predetermined position of the honeycomb formed body at time t is expressed by a function H (t), the amount of change in the height in the direction perpendicular to the extrusion direction of the honeycomb formed body is expressed as follows. Differentiated value. This amount of change is assumed to be H ′ (t).
In FIG. 12, when t = 0, H (0) = _Hb .
12, the case of _{0 <t <t a, H'} (t) <0 , and becomes the _H (t) <H _b. In such a case, it means that the shape distortion of the contraction rectangle is progressing.
For t = _{t a} in FIG. _{12, H'(t a) =} 0 becomes, H _{(t a)} is the limit value.
In FIG. 12, when t _a <t <t _b , 0 <H ′ (t) and H (t) <H _b . In such a case, it means that the shape distortion of the contraction rectangle is being eliminated.
12, the case of _{t = t b, 0 <H'} (t b) _{, and} becomes an _{H (t b) = H b} .
In FIG. 12, when t _b <t <t _c , 0 <H ′ (t) and H _b <H (t). In such a case, it means that the shape distortion of the swollen square is progressing.
In FIG. 12, when t = t _c , H ′ (t _c ) = 0, and H (t _c ) is a limit value.
In FIG. 12, when t _c <t <t _d , H ′ (t) <0 and H _b <H (t). In such a case, it means that the shape distortion of the swollen square is being eliminated.
In FIG. 12, when t = t _d , H ′ (t _d ) <0, and H (t _d ) = H _b .

In the extrusion molding apparatus according to the third embodiment of the present invention, when H (t) <H _b and H ′ (t) <0, it means that the shape distortion of the shrinking quadrangle is progressing. It is desirable to increase the flow rate of the cooling water. Further, when H (t)> _Hb and H ′ (t)> 0, it means that the shape distortion of the swollen square is progressing, so it is desirable to reduce the flow rate of the cooling water.

Further, an extrusion molding apparatus according to a third embodiment of the present invention, it is desirable that the difference between H (t _a) and H (t _c) to control the flow rate of the cooling water so as to decrease.
As a method of controlling the flow rate of the cooling water so that the difference between H (t _a ) and H (t _c ) becomes small, the predetermined time between the first time and the second time is shortened. Etc.

In the method for manufacturing a honeycomb formed body according to the third embodiment of the present invention, the height in the direction perpendicular to the extrusion direction of the honeycomb formed body measured in the height measurement step is one place, and the flow rate control step The method for manufacturing a honeycomb formed body according to the second embodiment of the present invention is the same except that the method for controlling the flow rate of the cooling water is different.
Since the measurement of the height in the direction perpendicular to the extrusion direction of the honeycomb formed body and the method for controlling the flow rate of the cooling water have already been described in the description of the extrusion apparatus according to the third embodiment of the present invention. Details are omitted.

The extrusion molding apparatus according to the third embodiment of the present invention and the method for manufacturing a honeycomb formed body using the extrusion molding apparatus according to the third embodiment of the present invention are described in the first embodiment of the present invention (1 ) And (2).

The extrusion molding apparatus of the present invention produces a kneaded material by kneading a raw material charging port for charging a raw material consisting of a wet mixture containing silicon carbide powder and a wet mixture charged into the raw material charging port with a screw, A kneading part that conveys the kneaded product to the extrusion molding part; and a tip part provided with a mold; and the kneaded material conveyed from the kneading part is pushed into the mold at the tip part by a screw, and Extrusion part for producing a continuous honeycomb formed body in which a large number of through-holes are juxtaposed in the longitudinal direction by extrusion through a mold, and the produced continuous honeycomb formed body is cut into a predetermined length and cut. A transport section for transporting the honeycomb formed body to the next step, and a pipe for flowing water for cooling the kneaded material is disposed at the tip portion by circulating cooling water therein, Flow The piping for the inflow for flowing in the flowing water into the tip end and the flow rate of the cooling water that is connected to and circulates the piping for discharging the flowing water for discharging the flowing water from the tip end A flow rate control mechanism for controlling the flow rate is disposed in at least one of the inflowing water piping and the flowing water piping, and the conveying unit is provided with respect to the extrusion direction of the manufactured honeycomb molded body. At least one height sensor for measuring the height in the vertical direction is arranged, and the flow rate of the cooling water is determined based on the height in the direction perpendicular to the extrusion direction of the honeycomb formed body measured by the height sensor. Control by the flow rate control mechanism is an essential constituent requirement. Various configurations described in detail in the first to third embodiments of the present invention (controlling the predetermined location of the honeycomb formed body to be measured, the timing, the number of height sensors, and the flow rate of cooling water) A desired effect can be obtained by appropriately combining the method and the like.

DESCRIPTION OF SYMBOLS 1 Extrusion molding apparatus 2 Raw material inlet 3 Kneading part 4 Extrusion part 5 Conveying part 40 Tip part 41 Mold 42 Flowing pipe 43 Flow control mechanism 44 Casing 45 Flowing pipe 46 for inflow 46 Flowing pipe 51 for discharge High Length sensor 52 Conveying member 53 Cutting member 60 Continuous honeycomb formed body 61 Honeycomb formed body 62, 72 Cell 63, 73 Cell wall 64, 74 Outer peripheral wall 71 Honeycomb fired body 75 Sealant 100 Upper screw mixer 101, 401 Receiving port 102 402 Kneading push roller 110 Kneading screw 111, 411 Feed screw 112 Tightening screw 113, 413 W blade screw 120 Die 130 Decompression chamber 140 Upper cutter 200 Lower screw mixer 400 Extrusion screw portion 410 Extrusion screw

Claims (8)

A raw material inlet for charging a raw material made of a wet mixture containing silicon carbide powder;
A kneaded part that kneads the wet mixture charged into the raw material charging port with a screw to produce a kneaded product, and conveys the kneaded product to an extrusion molding unit; and
A tip is provided with a mold, and the kneaded material conveyed from the kneading part is pushed into the mold at the tip by a screw, and is pushed out through the mold so that a large number of through holes are elongated. An extrusion molding part for producing continuous honeycomb molded bodies arranged in parallel in the direction;
It is an extrusion molding apparatus provided with a transport unit that cuts the manufactured continuous honeycomb formed body into a predetermined length and transports the cut honeycomb formed body to the next process,
A pipe for flowing water for cooling the kneaded material by circulating cooling water through the inside is disposed at the tip portion,
The flowing water pipe is connected to and circulates the flowing water pipe for flowing in the flowing water into the tip and the discharging water pipe for discharging the flowing water from the tip. A flow rate control mechanism for controlling the flow rate of the inflowing water pipe and at least one of the flowing water pipe,
At least one height sensor for measuring the height in the direction perpendicular to the extrusion direction of the produced honeycomb molded body is disposed in the transport unit,
The extrusion molding apparatus characterized in that the flow rate of the cooling water is controlled by the flow rate control mechanism based on the height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor. The height sensor is arranged in two units, the height of two different places of the honeycomb formed body is measured, and the flow rate of the cooling water is controlled based on the difference between the measured heights of the two places. The extrusion molding apparatus as described. The shape of the cross section perpendicular to the longitudinal direction of the honeycomb formed body is substantially quadrangular,
One of the height sensors measures the height (h1) in the direction perpendicular to the extrusion direction of the honeycomb formed body at the end of the upper side of the substantially square at every predetermined time,
The other height sensor measures the height (h2) in a direction perpendicular to the extrusion direction of the honeycomb molded body at an intermediate portion of the upper side of the substantially square shape at predetermined time intervals,
Based on the following formula (1), the distance difference (D) is calculated from the height (h1) and the height (h2) measured at the same time,
From the distance difference (D) calculated at each time, calculate the amount of change per unit time of the distance difference (D),
The flow rate control mechanism is
When the distance difference (D) is a positive value and the amount of change in the distance difference (D) per unit time is a positive value, the flow rate of the cooling water is increased,
The extrusion molding according to claim 2, wherein when the distance difference (D) is a negative value and the change amount of the distance difference (D) per unit time is a negative value, the flow rate of the cooling water is decreased. apparatus.
D = h1-h2 (1) The shape of the cross section perpendicular to the longitudinal direction of the honeycomb formed body is substantially quadrangular,
The height sensor is configured to set a height in a direction perpendicular to the extrusion direction of the honeycomb formed body at a middle portion of the upper side of the substantially square at a first time (t1) and a predetermined time from the first time. Measured at the second time (t2) after elapse of
The height in the direction perpendicular to the extrusion direction of the honeycomb formed body measured by the height sensor at the first time (t1) is defined as the height at the first time (H _t1 ).
The height in the direction perpendicular to the extrusion direction of the honeycomb formed body measured by the height sensor at the second time (t2) is defined as the height at the second time (H _t2 ).
When each side constituting the substantially quadrilateral is a straight line, the height (H _b ) is the height in the direction perpendicular to the extrusion direction of the honeycomb formed body in the middle portion of the upper side of the substantially quadrilateral.
When the flow rate per unit time of the cooling water flowing from the first time (t1) to the second time (t2) is defined as a flow rate (V _t1-t2 ),
The flow rate control mechanism is
The height (H _t1 ) at the first time is higher than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is the height. If it is lower than (H _b ), after measuring the height (H _t2 ) at the second time, the flow rate per unit time of the cooling water is increased above the flow rate (V _t1-t2 ),
The height (H _t1 ) at the first time is lower than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is the height. When higher than (H _b ), the flow rate per unit time of the cooling water is decreased from the flow rate (V _{t1 -t2} ) after the measurement of the height (H _t2 ) at the second time. Item 2. An extrusion apparatus according to Item 1. A method for manufacturing a honeycomb formed body using the extrusion molding apparatus according to claim 1,
Continuous honeycomb molding in which a raw material made of a wet mixture containing silicon carbide powder is fed from the raw material inlet through the mold of the extrusion molding section, and a large number of through holes are arranged in the longitudinal direction. A continuous honeycomb molded body manufacturing process for manufacturing the body,
A cutting step of cutting the continuous honeycomb formed body into a predetermined length by cutting to a predetermined length;
A height measuring step of measuring the height in a direction perpendicular to the extrusion direction of the honeycomb formed body by a height sensor while transporting the cut honeycomb formed body by a transport unit;
And a flow rate control step of controlling the flow rate of cooling water by a flow rate control mechanism based on the height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor. Body manufacturing method. In the height measurement step, two height sensors measure the height of two different locations of the honeycomb formed body, and control the flow rate of the cooling water based on the difference in height between the two measured heights. A method for manufacturing a honeycomb formed body according to claim 5. The shape of the cross section perpendicular to the longitudinal direction of the honeycomb formed body is substantially quadrangular,
In the height measuring step,
With the one height sensor, the height (h1) in the direction perpendicular to the extrusion direction of the honeycomb formed body at the end of the upper side of the substantially square is measured every predetermined time,
With the other height sensor, the height (h2) in the direction perpendicular to the extrusion direction of the honeycomb formed body at the middle portion of the upper side of the substantially square is measured every predetermined time,
Based on the following formula (1), the distance difference (D) is calculated from the height (h1) and the height (h2) measured at the same time,
From the distance difference (D) calculated at each time, calculate the amount of change per unit time of the distance difference (D),
In the flow rate control step, the flow rate control mechanism includes:
When the distance difference (D) is a positive value and the amount of change in the distance difference (D) per unit time is a positive value, the flow rate of the cooling water is increased,
The honeycomb forming according to claim 6, wherein when the distance difference (D) is a negative value and the amount of change in the distance difference (D) per unit time is a negative value, the flow rate of the cooling water is decreased. Body manufacturing method.
D = h1-h2 (1) The shape of the cross section perpendicular to the longitudinal direction of the honeycomb formed body is substantially quadrangular,
In the height measuring step, the height sensor determines the height in the direction perpendicular to the extrusion direction of the honeycomb molded body at the middle portion of the upper side of the substantially square at a first time (t1), and the first Measured at a second time (t2) after a predetermined time has elapsed from the time of 1,
The height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor at the first time (t1) is defined as the height at the first time (H _t1 ).
The height in the direction perpendicular to the extrusion direction of the honeycomb molded body measured by the height sensor at the second time (t2) is defined as the height at the second time (H _t2 ).
When each side constituting the substantially quadrilateral is a straight line, the height (H _b ) is the height in the direction perpendicular to the extrusion direction of the honeycomb formed body in the middle portion of the upper side of the substantially quadrilateral.
When the flow rate per unit time of the cooling water flowing from the first time (t1) to the second time (t2) is defined as a flow rate (V _t1-t2 ),
In the flow rate control step, by the flow rate control mechanism,
The height (H _t1 ) at the first time is higher than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is the height. If it is lower than (H _b ), after measuring the height (H _t2 ) at the second time, the flow rate per unit time of the cooling water is increased above the flow rate (V _t1-t2 ),
The height (H _t1 ) at the first time is lower than the height (H _t2 ) at the second time, and the height (H _t2 ) at the second time is the height. When higher than (H _b ), the flow rate per unit time of the cooling water is decreased from the flow rate (V _{t1 -t2} ) after the measurement of the height (H _t2 ) at the second time. Item 6. A method for manufacturing a honeycomb formed body according to Item 5.

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