Method for manufacturing cylindrical honeycomb sintered body

Abstract

The object of the present invention is to provide a method for manufacturing a cylindrical honeycomb fired body that helps improve the yield. The manufacturing method of the present invention comprises: step A, manufacturing a cylindrical honeycomb formed body; step B, drying the cylindrical honeycomb formed body to obtain a cylindrical honeycomb dried body; step C, for a cross section of the cylindrical honeycomb dried body perpendicular to the extension direction of the cells, calculating a predetermined parameter (E AVE1 、E AVE2 、E AVE3 and E AVE4 ); step D, determining the minimum value of the parameters calculated in step C; and step E, placing the cylindrical honeycomb dried body on a shelf in such a manner that the cell extension direction is parallel to the vertical direction and the portion of the predetermined peripheral side surface determined according to the minimum value is located at the front, and firing the cylindrical honeycomb dried body while passing it through a continuous firing furnace to obtain a cylindrical honeycomb fired body.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a cylindrical honeycomb sintered body. Background Art

[0002] The columnar honeycomb fired body is widely used for catalyst carriers, various filters, etc. Recently, it has attracted particular attention as an application in a diesel particulate filter (DPF) and a gasoline particulate filter (GPF) for capturing particulate matter (PM) exhausted from a diesel engine.

[0003] The columnar honeycomb fired body can be manufactured by kneading a raw material composition obtained by appropriately adding various additives to a ceramic raw material, a pore-forming material, a binder, and water to form a green clay, extruding it through a die defining a predetermined cellular structure to produce a columnar honeycomb formed body, cutting the honeycomb formed body into a predetermined length, drying it, and then firing it. An annular member called a mask or a pressing plate is installed adjacent to the downstream of the die used for extrusion molding to define the contour of the outer peripheral side of the columnar honeycomb formed body (for example: Japanese Patent No. 6376701).

[0004] Measuring the external dimensions of columnar honeycomb structures such as columnar honeycomb molded bodies and columnar honeycomb fired bodies is an important matter in quality management, and several measurement methods are known in the past. For example, in Japanese Patent Publication No. 7-260440, the following method is disclosed: an arm equipped with multiple laser displacement meters at different heights is rotated around an object to be measured placed on a plane perpendicular to the rotation axis of the arm to measure the three-dimensional external shape of the object to be measured. In Japanese Patent Publication No. 2002-267427, a method for measuring the external shape of a honeycomb structure is disclosed, characterized in that the end face of the honeycomb structure is photographed to obtain an original image, the average brightness of the outer wall portion of the honeycomb structure in the obtained original image is obtained, and on the original image, a full-coated image in which the interior of the honeycomb structure is filled with grayscale of the obtained average brightness is obtained, and the obtained full-coated image is subjected to edge detection processing to thereby measure the external shape.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 6376701

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 7-260440

[0009] Patent Document 3: Japanese Patent Application Publication No. 2002-267427 Summary of the invention

[0010] Problems to be solved by the invention

[0011] Shrinkage occurs during the firing process of the honeycomb formed body. Therefore, the design dimensions of the honeycomb formed body are determined by estimating the shrinkage in a way that the honeycomb fired body falls within the dimensional tolerance. It is believed that the reduction rate during shrinkage can be mastered by measuring the outer diameter dimensions before and after firing. However, the reduction rate is not uniform, and there is a problem that it varies depending on the location of the honeycomb formed body. Therefore, in the previous outer dimension measurement technology, although the outer dimensions of the honeycomb formed body and the honeycomb fired body can be mastered, there is no sufficient research on how to apply the measurement results of the outer dimensions to the firing conditions of the honeycomb fired body and the manufacturing conditions of the honeycomb formed body. It would be beneficial if the yield rate during the manufacture of the honeycomb fired body could be improved by making good use of the measurement results of the outer dimensions.

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a cylindrical honeycomb fired body, which can reduce the target to a desired large cylindrical honeycomb fired body among the cylindrical honeycomb fired bodies, thereby contributing to improving the yield.

[0013] Means for solving problems

[0014] In order to solve the above-mentioned problem, the inventors have studied the reason why the reduction rate during shrinkage varies depending on the part of the cylindrical honeycomb molded body. As a result, it was found that the reason is that the thermal history of the cylindrical honeycomb molded body in the firing furnace varies depending on the part of the cylindrical honeycomb molded body due to the position of the burner and the influence of the airflow in the furnace. Therefore, for example, even if the reduction rate is calculated on the premise that the cylindrical honeycomb molded body shrinks evenly, and the size of the cylindrical honeycomb molded body is determined based on the reduction rate, the dimensional accuracy of the part deviating from the reduction rate deteriorates because it is not actually shrunk evenly.

[0015] In addition, the inventors have found that even if the shrinkage rate during shrinkage is different depending on the location, it is not random, and when the cylindrical honeycomb molded body is fired while passing through a continuous firing furnace, a predetermined location on the outer peripheral side surface shrinks significantly. The present invention was completed based on this finding and is exemplified below. [1]

[0017] A method for manufacturing a cylindrical honeycomb fired body, wherein the cylindrical honeycomb fired body has an outer peripheral side surface and partition walls, wherein the partition walls are arranged on the inner peripheral side of the outer peripheral side surface and divide a plurality of cells forming a flow path from a first bottom surface to a second bottom surface,

[0018] The manufacturing method comprises:

[0019] Step A, extruding a clay containing a ceramic raw material, a pore-forming material, a binder and a dispersion medium through a die and an annular mask in an orientation in which the extending direction of the cells is horizontal, and cutting it into a predetermined length, thereby manufacturing a cylindrical honeycomb molded body having a front side in the traveling direction of the extrusion molding as a first bottom surface and a rear side as a second bottom surface, wherein the die defines the opening shape of the plurality of cells, and the annular mask is provided downstream of the die and has an inner peripheral contour for defining the outer peripheral contours of the first bottom surface and the second bottom surface;

[0020] Step B, drying the cylindrical honeycomb formed body to obtain a cylindrical honeycomb dried body;

[0021] In step C, assuming that a cross section perpendicular to the extending direction of the cells of the cylindrical honeycomb dried body is observed from the front side of the advancing direction of the extrusion molding in step A, the portion of the outer peripheral side surface located at the vertex during the extrusion molding in step A is set to 0 rad, the clockwise direction is set to the positive direction, and the average value of the distance between the center position O of the cross section with a central angle (rad) of -1 / 8π to +1 / 8π and the outer peripheral contour is set to D 1AVE , the average value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) of +1 / 8π to +3 / 8π is set as D 2AVE , the average value of the distance between the center of gravity position O of the cross section with a center angle (rad) of +3 / 8π to +5 / 8π and the outer contour is set as D 3AVE , the average value of the distance between the center of gravity position O of the cross section with a center angle (rad) of +5 / 8π to +7 / 8π and the outer contour is set as D 4AVE , the average value of the distance between the center of gravity position O of the cross section with a center angle (rad) of +7 / 8π to +9 / 8π and the outer contour is set as D 5AVE , the average value of the distance between the center position O of the cross section with a center angle (rad) of +9 / 8π to +11 / 8π and the outer contour is set as D 6AVE , the average value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) of +11 / 8π to +13 / 8π is set as D 7AVE , the average value of the distance between the center position O of the cross section and the outer contour with a center angle (rad) of +13 / 8π to +15 / 8π is set as D 8AVE , calculate:

[0022] (D 1AVE +D 4AVE +D 6AVE )-(D 2AVE +D 5AVE +D 8AVE )=E AVE1

[0023] (D 3AVE +D 6AVE +D 8AVE )-(D 2AVE +D 4AVE +D 7AVE )=E AVE2

[0024] (D 2AVE +D 5AVE +D 8AVE )-(D 1AVE +D 4AVE +D 6AVE )=E AVE3 ,as well as

[0025] (D 2AVE +D 4AVE +D 7AVE )-(D 3AVE +D 6AVE +D 8AVE )=E AVE4 ;

[0026] Step D, determine E calculated in step C AVE1 、E AVE2 、E AVE3 and E AVE4 The minimum value in ; and

[0027] Step E, in which the extending direction of the cells is parallel to the vertical direction and the minimum value is E AVE1 When the minimum value is E, the part of the outer peripheral side corresponding to 0rad is located at the front. AVE2 When the minimum value is E, the part of the outer peripheral side corresponding to 4 / 8πrad is located at the front. AVE3 When the minimum value is E, the part of the outer peripheral side corresponding to 8 / 8πrad is located at the front. AVE4 When the cylindrical honeycomb dried body is placed on a shelf in such a manner that the portion of the outer peripheral side surface corresponding to 12 / 8πrad is located at the front, the cylindrical honeycomb dried body is fired while passing through a continuous firing furnace to obtain a cylindrical honeycomb fired body. [2]

[0029] The manufacturing method as described in [1] comprises: in step B, on the basis of being arranged in a dryer with the extension direction of the cells becoming a vertical direction, drying is carried out while passing through the dryer in a manner such that the portion of the peripheral side surface located at the vertex when extrusion molding is performed in step A is located at the front. [3]

[0031] The manufacturing method described in [1] or [2], wherein it is determined whether the minimum value determined in step D satisfies a predetermined criterion, and step E is performed only when the minimum value satisfies the criterion. [4]

[0033] The manufacturing method as described in [3] includes: determining whether the minimum value determined in step D satisfies a predetermined criterion, and when the minimum value does not satisfy the predetermined criterion, not performing step E but performing step F of manufacturing an annular mask, wherein the annular mask changes the inner circumference contour according to the minimum value so that the E of the cylindrical honeycomb dried body to be manufactured next time is AVE1 、E AVE2 、E AVE3 and E AVE4 The minimum value in satisfies the predetermined benchmark, and then, steps A to D are repeated again using the changed annular mask. [5]

[0035] The manufacturing method as described in [3] or [4], wherein the predetermined reference is that the minimum value is in the range of -0.3 mm to -0.1 mm. [6]

[0037] The manufacturing method according to any one of [1] to [5], comprising: in step C, in order to calculate E AVE1 、E AVE2 、E AVE3 and E AVE4 , and carry out the following steps in sequence:

[0038] The step of placing the cylindrical honeycomb dried body on a rotating table with the first bottom surface or the second bottom surface facing upward; and

[0039] A step of continuously measuring the distance between any one point on the outer peripheral side surface of the cylindrical honeycomb dried body and the displacement meter using a displacement meter while rotating the rotating table once. [7]

[0041] A method for manufacturing a cylindrical honeycomb fired body, wherein the cylindrical honeycomb fired body has an outer peripheral side surface and partition walls, wherein the partition walls are arranged on the inner peripheral side of the outer peripheral side surface and divide a plurality of cells forming a flow path from a first bottom surface to a second bottom surface,

[0042] The manufacturing method comprises:

[0043] Step A, extruding a clay containing a ceramic raw material, a pore-forming material, a binder and a dispersion medium through a die and an annular mask in an orientation in which the extending direction of the cells is horizontal, and cutting it into a predetermined length, thereby manufacturing a cylindrical honeycomb molded body having a front side in the traveling direction of the extrusion molding as a first bottom surface and a rear side as a second bottom surface, wherein the die defines the opening shape of the plurality of cells, and the annular mask is provided downstream of the die and has an inner peripheral contour for defining the outer peripheral contours of the first bottom surface and the second bottom surface;

[0044] Step B, drying the cylindrical honeycomb formed body to obtain a cylindrical honeycomb dried body;

[0045] In step C, assuming that a cross section perpendicular to the extending direction of the cells of the cylindrical honeycomb dried body is observed from the front side of the advancing direction of the extrusion molding in step A, the portion of the outer peripheral side surface located at the vertex during the extrusion molding in step A is set to 0 rad, the clockwise direction is set to the positive direction, and the maximum value of the distance between the center position O of the cross section and the outer peripheral contour at the central angle (rad) from -1 / 8π to +1 / 8π is set to D 1MAX , the maximum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +1 / 8π to +3 / 8π is set as D 2MAX , the maximum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +3 / 8π to +5 / 8π is set as D 3MAX , the maximum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +5 / 8π to +7 / 8π is set as D 4MAX , the maximum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +7 / 8π to +9 / 8π is set as D 5MAX , the maximum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +9 / 8π to +11 / 8π is set as D 6MAX , the maximum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +11 / 8π to +13 / 8π is set as D 7MAX , the maximum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +13 / 8π to +15 / 8π is set as D 8MAX , calculate:

[0046] (D 1MAX +D 4MAX +D 6MAX )-(D 2MAX +D 5MAX +D 8MAX )=E MAX1

[0047] (D 3MAX +D 6MAX +D 8MAX )-(D 2MAX +D 4MAX +D 7MAX )=E MAX2

[0048] (D 2MAX +D 5MAX +D 8MAX )-(D 1MAX +D 4MAX +D 6MAX )=E MAX3 ,as well as

[0049] (D 2MAX +D 4MAX +D 7MAX )-(D 3MAX +D 6MAX +D 8MAX )=E MAX4 ;

[0050] Step D, determine E calculated in step C MAX1 、E MAX2 、E MAX3 and E MAX4 The minimum value in ; and

[0051] Step E, in which the extending direction of the cells is parallel to the vertical direction and the minimum value is E MAX1 When the minimum value is E, the part of the outer peripheral side corresponding to 0rad is located at the front. MAX2 When the minimum value is E, the part of the outer peripheral side corresponding to 4 / 8πrad is located at the front. MAX3 When the minimum value is E, the part of the outer peripheral side corresponding to 8 / 8πrad is located at the front. MAX4 When the cylindrical honeycomb dried body is placed on a shelf in such a manner that the portion of the outer peripheral side surface corresponding to 12 / 8πrad is located at the front, the cylindrical honeycomb dried body is fired while passing through a continuous firing furnace to obtain a cylindrical honeycomb fired body. [8]

[0053] The manufacturing method as described in [7] comprises: in step B, on the basis of being arranged in a dryer with the extension direction of the cells being in a vertical direction, drying is performed while passing through the dryer in a manner such that the portion of the peripheral side surface located at the vertex when extrusion molding is performed in step A is located at the front. [9]

[0055] The manufacturing method described in [7] or [8], wherein it is determined whether the minimum value determined in step D satisfies a predetermined criterion, and step E is performed only when the minimum value satisfies the criterion.

[10]

[0057] The manufacturing method as described in [9] includes: determining whether the minimum value determined in step D satisfies a predetermined criterion, and when the minimum value does not satisfy the predetermined criterion, not performing step E but performing step F of manufacturing an annular mask, wherein the annular mask changes the inner circumference contour according to the minimum value so that the E of the cylindrical honeycomb dried body to be manufactured next time is MAX1 、E MAX2 、E MAX3 and E MAX4 The minimum value in satisfies the predetermined benchmark, and then, steps A to D are repeated again using the changed annular mask.

[11]

[0059] The manufacturing method according to [9] or

[10] , wherein the predetermined criterion is that the minimum value is in the range of -0.3 mm to -0.1 mm.

[12]

[0061] The manufacturing method according to any one of [7] to

[11] , comprising: in step C, in order to calculate E MAX1 、E MAX2 、E MAX3 and E MAX4 , and carry out the following steps in sequence:

[0062] The step of placing the cylindrical honeycomb dried body on a rotating table with the first bottom surface or the second bottom surface facing upward; and

[0063] A step of continuously measuring the distance between any one point on the outer peripheral side surface of the cylindrical honeycomb dried body and the displacement meter using a displacement meter while rotating the rotating table once.

[13]

[0065] A method for manufacturing a cylindrical honeycomb fired body, wherein the cylindrical honeycomb fired body has an outer peripheral side surface and partition walls, wherein the partition walls are arranged on the inner peripheral side of the outer peripheral side surface and divide a plurality of cells forming a flow path from a first bottom surface to a second bottom surface,

[0066] The manufacturing method comprises:

[0067] Step A, extruding a clay containing a ceramic raw material, a pore-forming material, a binder and a dispersion medium through a die and an annular mask in an orientation in which the extending direction of the cells is horizontal, and cutting it into a predetermined length, thereby manufacturing a cylindrical honeycomb molded body having a front side in the traveling direction of the extrusion molding as a first bottom surface and a rear side as a second bottom surface, wherein the die defines the opening shape of the plurality of cells, and the annular mask is provided downstream of the die and has an inner peripheral contour for defining the outer peripheral contours of the first bottom surface and the second bottom surface;

[0068] Step B, drying the cylindrical honeycomb formed body to obtain a cylindrical honeycomb dried body;

[0069] In step C, assuming that a cross section perpendicular to the extending direction of the cells of the cylindrical honeycomb dried body is observed from the front side of the advancing direction of the extrusion molding in step A, the portion of the outer peripheral side surface located at the vertex during the extrusion molding in step A is set to 0 rad, the clockwise direction is set to the positive direction, and the minimum value of the distance between the center position O of the cross section and the outer peripheral contour at the central angle (rad) from -1 / 8π to +1 / 8π is set to D 1MIN , the minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +1 / 8π to +3 / 8π is set as D 2MIN , the minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +3 / 8π to +5 / 8π is set as D 3MIN , the minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +5 / 8π to +7 / 8π is set as D 4MIN , the minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +7 / 8π to +9 / 8π is set as D 5MIN , the minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +9 / 8π to +11 / 8π is set as D 6MIN , the minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +11 / 8π to +13 / 8π is set as D 7MIN , the minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +13 / 8π to +15 / 8π is set as D 8MIN , calculate:

[0070] (D 1MIN +D 4MIN +D 6MIN )-(D 2MIN +D 5MIN +D 8MIN )=E MIN1

[0071] (D 3MIN +D 6MIN +D 8MIN )-(D 2MIN +D 4MIN +D 7MIN )=E MIN2

[0072] (D 2MIN +D 5MIN +D 8MIN )-(D 1MIN +D 4MIN +D 6MIN )=E MIN3 ,as well as

[0073] (D 2MIN +D 4MIN +D 7MIN )-(D 3MIN +D 6MIN +D 8MIN )=E MIN4 ;

[0074] Step D, determine E calculated in step C MIN1 、E MIN2 、E MIN3 and E MIN4 The minimum value in ; and

[0075] Step E, in which the extending direction of the cells is parallel to the vertical direction and the minimum value is E MIN1 When the minimum value is E, the part of the outer peripheral side corresponding to 0rad is located at the front. MIN2 When the minimum value is E, the part of the outer peripheral side corresponding to 4 / 8πrad is located at the front. MIN3 When the minimum value is E, the part of the outer peripheral side corresponding to 8 / 8πrad is located at the front. MIN4 When the cylindrical honeycomb dried body is placed on a shelf in such a manner that the portion of the outer peripheral side surface corresponding to 12 / 8πrad is located at the front, the cylindrical honeycomb dried body is fired while passing through a continuous firing furnace to obtain a cylindrical honeycomb fired body.

[14]

[0077] The manufacturing method as described in

[13] comprises: in step B, on the basis of being arranged in a dryer with the extension direction of the cells being in a vertical direction, drying is performed while passing through the dryer in a manner such that the portion of the peripheral side surface located at the vertex during extrusion molding in step A is located at the front.

[15]

[0079] The manufacturing method described in

[13] or

[14] , wherein it is determined whether the minimum value determined in step D satisfies a predetermined criterion, and step E is performed only when the minimum value satisfies the criterion.

[16]

[0081] The manufacturing method as described in

[15] comprises: determining whether the minimum value determined in step D satisfies a predetermined criterion, and when the minimum value does not satisfy the predetermined criterion, not performing step E but performing step F of manufacturing an annular mask, wherein the annular mask changes the inner circumference contour according to the minimum value so that the E of the cylindrical honeycomb dried body to be manufactured next time is MIN1 、E MIN2 、E MIN3 and E MIN4 The minimum value in satisfies the predetermined benchmark, and then, steps A to D are repeated again using the changed annular mask.

[17]

[0083] The manufacturing method as described in

[15] or

[16] , wherein the predetermined criterion is that the minimum value is in the range of -0.3 mm to -0.1 mm.

[18]

[0085] The manufacturing method as described in any one of

[13] to

[17] , comprising: in step C, in order to calculate E MIN1 、E MIN2 、E MIN3 and E MIN4 , and carry out the following steps in sequence:

[0086] The step of placing the cylindrical honeycomb dried body on a rotating table with the first bottom surface or the second bottom surface facing upward; and

[0087] A step of continuously measuring the distance between any one point on the outer peripheral side surface of the cylindrical honeycomb dried body and the displacement meter using a displacement meter while rotating the rotating table once.

[0088] Effects of the Invention

[0089] According to the manufacturing method of the cylindrical honeycomb fired body involved in one embodiment of the present invention, the yield rate during the manufacturing of the cylindrical honeycomb fired body is improved. For example, even if the cylindrical honeycomb dried body as the semi-finished product of the cylindrical honeycomb fired body has a dimensional error at a level that was not allowed in the past, it is possible to adjust the direction of the cylindrical honeycomb dried body when passing through the continuous firing furnace based on the shape of the cylindrical honeycomb dried body with the dimensional error, thereby manufacturing a cylindrical honeycomb fired body within the range of the dimensional tolerance. That is, the dimensional tolerance of the cylindrical honeycomb dried body at the stage can be alleviated, so the yield rate is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] Figure 1 It is a perspective view schematically showing a wall-through type honeycomb sintered body.

[0091] Figure 2 This is a schematic cross-sectional view of a wall-filter type honeycomb fired body when viewed from a direction perpendicular to the extending direction of cells.

[0092] Figure 3 It is a perspective view schematically showing a wall-flow type honeycomb sintered body.

[0093] Figure 4 This is a schematic cross-sectional view of a wall flow type honeycomb fired body observed from a direction perpendicular to the extending direction of the cells.

[0094] Figure 5 It is a schematic diagram showing the cross-sectional structure of the extrusion molding device when viewed from a direction perpendicular to the extrusion direction.

[0095] Figure 6 is a schematic front view of a ring mask.

[0096] Figure 7 This is a schematic perspective view for explaining the structure of a shape measuring device suitable for performing step C using a displacement meter.

[0097] Figure 8 This is a schematic diagram for explaining a method of obtaining the distance (radius R) between the center of gravity position O and the outer peripheral contour in the cross section of a cylindrical dried honeycomb body using a displacement meter.

[0098] Fig. 9 It is used to illustrate the cross section of the cylindrical honeycomb drying body and D 1AVE , D 2AVE , D 3AVE , D 4AVE , D 5AVE , D 6AVE , D 7AVE , D 8AVE Schematic diagram of the relationship.

[0099] Fig.10 This is a schematic diagram for explaining the relationship between the advancing direction of the cylindrical honeycomb dried body in the firing furnace and the portion of the outer peripheral side surface where the firing shrinkage is large.

[0100] Explanation of symbols

[0101] 100: cylindrical honeycomb sintered body, 102: outer peripheral side, 103: outer peripheral side wall, 104: first bottom surface, 106: second bottom surface, 108: cells, 112: partition wall, 200: cylindrical honeycomb sintered body, 202: outer peripheral side, 203: outer peripheral side wall, 204: first bottom surface, 206: second bottom surface, 208a: first cells, 208b: second cells, 209: sealing part, 212: partition wall, 500: extrusion molding device, 510: die, 511: inner part, 5 11a: slit, 512: outer peripheral portion, 512a: slit, 513: step portion, 520: annular mask, 522: inner peripheral contour, 530: gap portion, 540: pressing fixture, 550: back pressure plate, 560: cylindrical honeycomb forming body, 700: shape measuring device, 710: rotating table, 720: displacement meter, 722: laser, 740: computer, 750: cylindrical honeycomb drying body, 753: outer peripheral side, 753a: location of the outer peripheral side, 770: Z workbench. DETAILED DESCRIPTION

[0102] Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiments, and it should be understood that design changes and improvements can be appropriately applied based on the common knowledge of those skilled in the art without departing from the gist of the present invention.

[0103] (1. Cylindrical honeycomb sintered body)

[0104] According to one embodiment of the present invention, a method for manufacturing a cylindrical honeycomb sintered body is provided. There is no particular limitation on the use of the cylindrical honeycomb sintered body. For example, it can be used for various industrial purposes such as radiators, filters (such as GPF, DPF), catalyst carriers, sliding parts, nozzles, heat exchangers, electrical insulation parts, and parts for semiconductor manufacturing equipment.

[0105] exist Figure 1 and Figure 2, a schematic perspective view and a cross-sectional view of a cylindrical honeycomb fired body 100 that can be used as a wall filter type automobile exhaust gas filter and / or a catalyst carrier are illustrated respectively. The cylindrical honeycomb fired body 100 has a cylindrical honeycomb structure portion, which includes: an outer peripheral side wall 103 having an outer peripheral side surface 102; and a partition wall 112, which is arranged on the inner peripheral side of the outer peripheral side wall 103 and divides a plurality of cells 108 that form a flow path from the first bottom surface 104 to the second bottom surface 106. In the cylindrical honeycomb fired body 100, both ends of each cell 108 are open, and the exhaust gas flowing into one cell 108 from the first bottom surface 104 is purified while passing through the cell 108, and flows out from the second bottom surface 106. The second bottom surface 106 can also be used as the inflow side of the exhaust gas, and the first bottom surface 104 can be used as the outflow side of the exhaust gas.

[0106] exist Figure 3 and Figure 4 , a schematic perspective view and a cross-sectional view of a cylindrical honeycomb sintered body 200 that can be used as a wall-flow type automobile exhaust gas filter and / or a catalyst carrier are illustrated respectively. The cylindrical honeycomb sintered body 200 has a cylindrical honeycomb structure portion, which has: an outer peripheral side wall 203, which has an outer peripheral side surface 202; and a partition wall 212, which is arranged on the inner peripheral side of the outer peripheral side wall 203 and divides a plurality of cells 208a, 208b that form a flow path for a fluid from a first bottom surface 204 to a second bottom surface 206.

[0107] In the cylindrical honeycomb fired body 200, the plurality of cells 208a and 208b can be classified into a plurality of first cells 208a and a plurality of second cells 208b, wherein the plurality of first cells 208a are arranged inside the outer peripheral side wall 203, extending from the first bottom surface 204 to the second bottom surface 206, the first bottom surface 204 is open and the second bottom surface 206 has a plugging portion 209, and the plurality of second cells 208b are arranged inside the outer peripheral side wall 203, extending from the first bottom surface 204 to the second bottom surface 206, the first bottom surface 204 has a plugging portion 209 and the second bottom surface 206 is open. Furthermore, in the cylindrical honeycomb fired body 200, the first cells 208a and the second cells 208b are alternately arranged adjacent to each other with the partition wall 212 interposed therebetween.

[0108] If exhaust gas containing soot is supplied to the first bottom surface 204 on the upstream side of the cylindrical honeycomb sintered body 200, the exhaust gas is introduced into the first cell 208a and moves downstream in the first cell 208a. Since the second bottom surface 206 on the downstream side of the first cell 208a is sealed, the exhaust gas flows into the second cell 208b through the partition 212 that divides the first cell 208a and the second cell 208b. Since the soot cannot pass through the partition 212, it is captured and accumulated in the first cell 208a. After the soot is removed, the clean exhaust gas that flows into the second cell 208b moves downstream in the second cell 208b and flows out from the second bottom surface 206 on the downstream side. The second bottom surface 206 can also be used as the inlet side of the exhaust gas, and the first bottom surface 204 can be used as the outlet side of the exhaust gas.

[0109] The material constituting the cylindrical honeycomb sintered body is not limited, and ceramics can be cited. The types of ceramics include cordierite, mullite, zirconium phosphate, aluminum titanate, silicon carbide (SiC), silicon-silicon carbide composite materials (e.g., Si combined with SiC), cordierite-silicon carbide composites, zirconium oxide, spinel, India stone, sapphire, corundum, titanium dioxide, silicon nitride, etc. Moreover, these ceramics can contain one alone or two or more.

[0110] The height of the cylindrical honeycomb sintered body (the length from the first bottom surface to the second bottom surface) is not particularly limited and can be appropriately set according to the application and required performance. There is no particular restriction on the relationship between the height of the cylindrical honeycomb sintered body and the diameter of each bottom surface. Therefore, the height of the cylindrical honeycomb sintered body can be longer than the diameter of each bottom surface, or the height of the cylindrical honeycomb sintered body can be shorter than the diameter of each bottom surface.

[0111] The size of each bottom area of ​​the cylindrical honeycomb fired body is not particularly limited, but in one embodiment, it can be set to 40 to 250 cm 2 In other embodiments, it can be set to 80 to 220 cm 2 In another embodiment, it can be set to 120-200 cm 2 .

[0112] The height of the cylindrical honeycomb fired body (the flow path length of each cell) is not particularly limited, and may be 40 to 200 mm in one embodiment, 60 to 180 mm in another embodiment, and 80 to 160 mm in yet another embodiment.

[0113] The bottom surface shape of the cylindrical honeycomb sintered body and the cross-sectional shape perpendicular to the extension direction of the cells are circular (designed to be a perfect circle). The "circle" in this specification includes not only a perfect circle, but also a circle with dimensional errors during manufacturing. Therefore, the bottom surface shape of the cylindrical honeycomb sintered body and the cross-sectional shape perpendicular to the extension direction of the cells are sometimes not actually perfect circles, but are required to be within the range of a predetermined dimensional tolerance. For example, if the roundness is in the range of 2.0 mm or less, it is allowed, preferably in the range of 1.6 mm or less. In this specification, regarding the roundness of the cylindrical honeycomb sintered body (the same applies to the dried body and the molded body), assuming that the cross section of the cylindrical honeycomb sintered body perpendicular to the extension direction of the cells and located at the center of the height of the cylindrical honeycomb sintered body is observed, the maximum value of the distance between the center of gravity position O of the cross section and the outer contour when measured in the circumferential direction for one circle is set to R. MAX , the minimum value is set to R MIN , use roundness = R MAX -R MIN The roundness can be measured using a displacement meter in the same manner as the sagging amount described later.

[0114] The shape of the cells in the cross section perpendicular to the extending direction of the cells is not limited, but is preferably a quadrilateral, a hexagon, an octagon, or a combination thereof. Among them, a square and a hexagon are preferred. By setting the cell shape in this way, the pressure loss when the fluid flows into the cylindrical honeycomb sintered body can be reduced.

[0115] From the viewpoint of ensuring the strength of the cylindrical honeycomb sintered body, the thickness of the partition wall is preferably 50 μm or more, more preferably 60 μm or more, and further more preferably 70 μm or more. In addition, from the viewpoint of suppressing the pressure loss when the fluid flows into the cylindrical honeycomb sintered body, the thickness of the partition wall is preferably 150 μm or less, more preferably 130 μm or less, and further more preferably 100 μm or less. In this specification, the thickness of the partition wall refers to the length of the line segment crossing the partition wall when the center of gravity of adjacent cells is connected to each other by a line segment in a cross section orthogonal to the extension direction of the cells. The average thickness of the partition wall refers to the average value of the thickness of all the partition walls.

[0116] The cell density (the number of cells per unit cross-sectional area perpendicular to the cell extension direction) is not particularly limited, and can be, for example, 6 to 2000 cells / square inch (0.9 to 311 cells / cm 2 ), more preferably 50 to 1000 cells / square inch (7.8 to 155 cells / cm 2 ), particularly preferably 100 to 600 cells / square inch (15.5 to 92.0 cells / cm 2Here, the cell density is calculated by dividing the total number of cells in the bottom surface of one side of the cylindrical honeycomb fired body (when there are sealed cells, it is calculated as if the cells are not sealed) by the bottom area of ​​the cylindrical honeycomb fired body on the side excluding the outer peripheral side wall.

[0117] The partition wall may be porous. The porosity of the partition wall can be appropriately adjusted according to the purpose. From the viewpoint of suppressing the pressure loss of the fluid to be low, it is preferably 25% or more, more preferably 35% or more, and further more preferably 45% or more. In addition, from the viewpoint of ensuring the strength of the cylindrical honeycomb sintered body, the porosity of the partition wall is preferably 80% or less, more preferably 75% or less, and further more preferably 70% or less. The porosity is measured by mercury porosimetry using a mercury porosimeter in accordance with JISR1655:2003.

[0118] When the cylindrical honeycomb sintered body is used as a catalyst carrier, a catalyst corresponding to the purpose can be coated on the surface of the partition wall. The catalyst is not limited, and examples thereof include: an oxidation catalyst (DOC) for oxidizing and burning hydrocarbons (HC) and carbon monoxide (CO) to increase the exhaust gas temperature, a PM combustion catalyst for assisting the combustion of PM such as soot, and a catalyst for removing nitrogen oxides (NO x ) and a three-way catalyst capable of simultaneously removing hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx). The catalyst may contain, for example, a noble metal (Pt, Pd, Rh, etc.), an alkali metal (Li, Na, K, Cs, etc.), an alkaline earth metal (Mg, Ca, Ba, Sr, etc.), a rare earth (Ce, Sm, Gd, Nd, Y, La, Pr, etc.), a transition metal (Mn, Fe, Co, Ni, Cu, Zn, Sc, Ti, Zr, V, Cr, etc.), etc.

[0119] (2. Method for manufacturing cylindrical honeycomb fired body)

[0120] Hereinafter, each step of the method for producing a cylindrical honeycomb fired body according to one embodiment of the present invention will be described in detail.

[0121] (Step A: Preparation of cylindrical honeycomb molded body)

[0122] In step A, a clay containing a ceramic raw material, a pore-forming material, a binder and a dispersion medium is extruded through a die and an annular mask, the die defining the opening shape of a plurality of cells, and the annular mask is arranged downstream of the die and has an inner peripheral contour for defining the outer peripheral contour of the first bottom surface and the second bottom surface. Extrusion molding is carried out with the extension direction of the cells as the horizontal direction. After extrusion molding, it is cut to a predetermined length by a cutting unit such as a cutter, thereby making a cylindrical honeycomb molded body. In the obtained cylindrical honeycomb molded body, the bottom surface on the front side of the direction of travel of the extrusion molding is called the first bottom surface, and the bottom surface on the rear side is called the second bottom surface.

[0123] Ceramic raw materials are raw materials that remain after the firing of metal oxides and metals, etc. and constitute the skeleton of the honeycomb fired body as ceramics. Ceramic raw materials can be provided in the form of powder, for example. As ceramic raw materials, raw materials for obtaining ceramics such as cordierite, mullite, zircon, aluminum titanate, silicon carbide, silicon nitride, zirconium oxide, spinel, India stone, sapphire, corundum, titanium dioxide, etc. can be cited. Specifically, although not limited, silicon dioxide, talc, aluminum oxide, kaolin, serpentine, pyrophyllite, brucite, boehmite, mullite, magnesite, aluminum hydroxide, etc. can be cited. Ceramic raw materials can be used alone or in combination of two or more.

[0124] In the case of filter applications such as DPF and GPF, cordierite can be suitably used as ceramic. In this case, a cordierite-forming raw material can be used as a ceramic raw material. The cordierite-forming raw material refers to a raw material that becomes cordierite by firing. The cordierite-forming raw material is preferably composed of a chemical composition of 30 to 45% by mass of aluminum oxide (Al2O3) (including the portion of aluminum hydroxide converted into aluminum oxide), 11 to 17% by mass of magnesium oxide (MgO), and 42 to 57% by mass of silicon dioxide (SiO2).

[0125] As a pore-forming material, as long as it is a material that becomes pores after firing, it is not particularly limited, for example, wheat flour, starch, foaming resin, water-absorbing resin, silica gel, carbon (e.g., graphite), ceramic microspheres, polyethylene, polystyrene, polypropylene, nylon, polyester, acrylic, phenol, foamed foamed resin, unfoamed foamed resin, etc. can be cited. One type of pore-forming material can be used alone, or two or more types can be used in combination. From the viewpoint of improving the porosity of the cylindrical honeycomb fired body, the content of the pore-forming material is preferably 0.5 parts by mass or more relative to 100 parts by mass of the ceramic raw material, more preferably 2 parts by mass or more, and further more preferably 3 parts by mass or more. From the viewpoint of ensuring the strength of the cylindrical honeycomb fired body, the content of the pore-forming material is preferably less than 10 parts by mass relative to 100 parts by mass of the ceramic raw material, more preferably less than 7 parts by mass, and further more preferably less than 4 parts by mass.

[0126] As the binder, organic binders such as methylcellulose, hydroxypropyl methylcellulose, hydroxypropoxy cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, etc. can be exemplified. Particularly suitable for using methylcellulose and hydroxypropoxy cellulose. In addition, from the viewpoint of improving the strength of the honeycomb formed body, the content of the binder is preferably more than 4 mass parts, more preferably more than 5 mass parts, and further more preferably more than 6 mass parts relative to 100 mass parts of raw materials. From the viewpoint of suppressing the cracking caused by abnormal heating in the firing process, the content of the binder is preferably less than 9 mass parts, more preferably less than 8 mass parts, and further more preferably less than 7 mass parts relative to 100 mass parts of ceramic raw materials. One kind of binder can be used alone, or two or more kinds can be used in combination.

[0127] As the dispersion medium, water or a mixed solvent of water and an organic solvent such as alcohol can be cited, and water is particularly suitable. The content of the dispersion medium of the cylindrical honeycomb molded body is preferably 20 to 90 parts by mass, more preferably 60 to 85 parts by mass, and further more preferably 70 to 80 parts by mass relative to 100 parts by mass of the ceramic raw material. By making the water content of the cylindrical honeycomb molded body more than 20 parts by mass relative to 100 parts by mass of the ceramic raw material, it is easy to obtain the advantage that the quality of the cylindrical honeycomb molded body is easy to stabilize. By making the water content of the cylindrical honeycomb molded body less than 90 parts by mass relative to 100 parts by mass of the ceramic raw material, the shrinkage during drying is reduced, and deformation can be suppressed. In this specification, the water content of the cylindrical honeycomb molded body refers to the value measured by the drying loss method.

[0128] The green clay may be mixed with additives such as a dispersant as needed. As the dispersant, ethylene glycol, dextrin, fatty acid soap, polyether polyol, etc. may be used. The dispersant may be used alone or in combination of two or more. The content of the dispersant is preferably 0 to 2 parts by mass relative to 100 parts by mass of the ceramic raw material.

[0129] Figure 5 The cross-sectional structure of the extrusion molding device when viewed from a direction perpendicular to the extrusion direction is schematically shown. The extrusion molding device 500 includes a die 510 and an annular mask 520 disposed on the downstream side of the die 510. The die 510 has slits 511a and 512a for extruding the molding raw material. In the extrusion molding device 500, the die 510 has an inner portion 511 and an outer portion 512. The inner portion 511 is directed downstream ( Figure 5The inner portion 511 is provided with a slit 511a which defines a honeycomb structure having a desired cell shape, partition wall thickness, cell density, etc. The outer peripheral portion 512 is provided with a slit 512a which is shorter than the slit 511a of the inner portion 511. A gap portion 530 for molding the outer peripheral side wall of the honeycomb structure is formed between the die 510 and the annular mask 520. A back pressure plate 550 for fixing the die 510 is installed on the upstream side of the die 510. Furthermore, a pressing fixture 540 installed in a manner of surrounding the outer peripheral side of the annular mask 520, the outer peripheral side of the die 510, and the outer peripheral side of the back pressure plate 550 from the downstream side of the annular mask 520 plays a role as a retainer for fixing the die 510 and the annular mask 520.

[0130] In the extrusion molding using the extrusion molding device 500, the molding material is introduced from the upstream side ( Figure 5 The molding material is extruded toward the downstream side through the die 510 by an extruder (not shown). Moreover, the molding material extruded from the slit 511a provided in the inner part 511 of the die 510 opened on the downstream side forms a honeycomb structure part having a plurality of cells. On the other hand, the molding material extruded from the slit 512a provided in the outer peripheral part 512 of the die 510 is flattened due to the action of the gap part 530, and the moving direction is changed from the extrusion direction to the direction along the step part 513. If the molding material is separated from the gap part 530, the moving direction is changed again to the extrusion direction to form an outer peripheral side wall surrounding the cells. In this way, a cylindrical honeycomb molded body 560 is continuously molded from the extrusion molding device 500. In this embodiment, the direction of extrusion molding is horizontal, and the extrusion molding is performed in a direction in which the extension direction of the cells becomes the horizontal direction. If the direction of extrusion molding is horizontal, it is conducive to continuously molding a long cylindrical honeycomb molded body.

[0131] Figure 6 , a schematic front view of the annular mask 520 is shown. The annular mask 520 has an inner peripheral contour 522 for defining the outer peripheral contours of the first bottom surface and the second bottom surface of the cylindrical honeycomb formed body. The inner peripheral contour 522 of the annular mask 520 used in step A may be similar in shape to the designed contours of the first bottom surface and the second bottom surface of the cylindrical honeycomb formed body, or may be a non-similar shape.

[0132] In addition to the case where the cylindrical honeycomb formed body is not a perfect circle due to dimensional errors during extrusion molding, there is also the case where it is intentionally not made into a perfect circle in consideration of the non-uniformity of the firing shrinkage in the subsequent firing process, but it is required to be within the range of a predetermined dimensional tolerance. For example, the cylindrical honeycomb formed body is allowed as long as the roundness is within the range of 2.0 mm or less, preferably within the range of 1.6 mm or less. The method for measuring the roundness is as described above.

[0133] (Step B: Drying of cylindrical honeycomb molded body)

[0134] Next, step B is implemented to dry the cylindrical honeycomb molded body to obtain a cylindrical honeycomb dried body. In the drying step, for example, previously known drying methods such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, and freeze drying can be used. Among them, from the aspect of being able to quickly and evenly dry the entire molded body, a drying method that combines hot air drying with microwave drying or dielectric drying is preferred. There is no particular restriction on the orientation of the cylindrical honeycomb molded body in step B. In addition, an intermittent dryer can be used, and a continuous dryer can also be used. In consideration of mass production and quality stability, it is preferred that the cylindrical honeycomb molded body is arranged in the dryer in a direction in which the extension direction of the cells becomes a vertical direction, and the cylindrical honeycomb molded body is dried while passing through the dryer in a manner such that the portion of the outer peripheral side surface located at the vertex when extrusion molding is performed in step A is located at the front.

[0135] When forming a sealing portion, the sealing portion is formed on both bottom surfaces of the dried cylindrical honeycomb formed body, and then the sealing portion is dried to obtain a cylindrical honeycomb dried body. There is no particular restriction on the material of the sealing portion, and from the viewpoint of strength and heat resistance, it is preferably a ceramic. As a ceramic, it is preferably a ceramic containing at least one selected from the group consisting of cordierite, mullite, zircon, aluminum titanate, silicon carbide, silicon nitride, zirconium oxide, spinel, India stone, sapphire, corundum and titanium dioxide. The sealing portion is preferably formed by a material containing more than 50% by mass of these ceramics in total, and more preferably by a material containing more than 80% by mass of these ceramics. Since the expansion coefficient during firing can be made the same, resulting in an improvement in durability, the sealing portion is further preferably composed of the same material as the main body of the honeycomb formed body.

[0136] The method for forming the sealing portion is described illustratively. The sealing slurry is stored in a storage container in advance. Then, a mask having an opening is attached to one bottom surface at a position corresponding to the pores where the sealing portion is to be formed. The bottom surface to which the mask is attached is immersed in the storage container, and the sealing slurry is filled in the opening to form the sealing portion. The sealing portion can also be formed on the other bottom surface by the same method.

[0137] (Step C: Measuring the amount of sagging of a cylindrical honeycomb dried body)

[0138] In step C, a predetermined parameter (E) is calculated based on the average value of the distance between the center of gravity position O and the outer peripheral contour within a predetermined plurality of angle ranges, assuming that the cross section perpendicular to the extending direction of the cells of the cylindrical dried honeycomb body is observed from the front side in the advancing direction of the extrusion molding in step A. AVE1 、E AVE2 、E AVE3 and E AVE4 ). In this specification, the value of this parameter is referred to as "droop amount". In order to directly observe the cross section of the cylindrical honeycomb dried body perpendicular to the extension direction of the cells, the cylindrical honeycomb dried body needs to be cut, but the cylindrical honeycomb dried body in the middle of manufacturing cannot be destroyed. Therefore, step C calculates the droop amount when the cross section is observed from the front side of the advancing direction of the extrusion molding in step A.

[0139] The calculation of the sagging amount when observing the cross section of the cylindrical honeycomb dried body perpendicular to the extension direction of the cells from the front side of the direction of travel of the extrusion molding in step A can be performed non-destructively using a displacement meter, for example. The type of displacement meter is not particularly limited, and examples thereof include optical, eddy current, ultrasonic, laser focusing, etc. In one embodiment, in step C, the following steps are performed: In order to calculate E AVE1 、E AVE2 、E AVE3 and E AVE4 , a process of placing a cylindrical honeycomb dried body on a rotating table with the first bottom surface or the second bottom surface as the upper side; and a process of continuously measuring the distance between any point on the outer peripheral side surface of the cylindrical honeycomb dried body and the displacement meter using a displacement meter while rotating the rotating table one circle.

[0140] exist Figure 7 , a schematic perspective view for explaining the structure of a shape measuring device 700 suitable for implementing step C using a displacement meter is shown. In one embodiment, the shape measuring device 700 may include: a rotating table 710 on which a cylindrical honeycomb dried body 750 is mounted and can rotate around a rotation axis A; a displacement meter 720 on which a laser beam 722 can be irradiated to an outer peripheral side surface 753 of the cylindrical honeycomb dried body 750; a computer 740 on which a sag amount can be calculated based on a measurement result of the displacement meter 720; and a Z table 770 on which the displacement meter 720 is mounted and can move in a vertical direction.

[0141] The rotating table 710 is configured to be rotatable at a predetermined rotation speed by a driving unit such as a servo motor about a rotation axis A extending in the vertical direction. The servo motor can be equipped with an encoder for detecting a displacement such as a rotation angle of the rotating table 710 .

[0142] The Z stage 770 can be moved by a driving unit such as a motor. For example, the Z stage 770 can be formed using an electric actuator such as an electric cylinder. The electric actuator can be composed of a linear guide, a ball screw, a servo motor, etc. The servo motor can be equipped with an encoder for detecting the displacement of the Z stage 770.

[0143] The implementation steps of step C using the shape measuring device 700 are described illustratively. First, the cylindrical honeycomb dried body 750 is placed on the rotating table 710 with the first bottom surface or the second bottom surface as the upper side. When the cylindrical honeycomb dried body 750 is placed on the rotating table 710, the distance between the center of gravity position O of the upper bottom surface (the first bottom surface or the second bottom surface) and the rotation axis A of the rotating table 710 does not necessarily need to be 0. Even if the two are separated, the radius R (the distance between the center of gravity position O and the outer peripheral contour) described later can be geometrically calculated, and can also be automatically calculated by the displacement meter. It is preferred to place the body in such a manner that the distance is usually 30 mm or less, preferably 20 mm or less, and more preferably 10 mm or less. As a result, the following advantages are obtained: when the cylindrical honeycomb dried body 750 rotates on the rotating table 710, the eccentricity becomes less, and the measurement using the displacement meter is stable.

[0144] Next, the height position of the outer peripheral side surface 753 of the cylindrical honeycomb dried body 750 placed on the rotating table 710 to be irradiated with the laser 722 is adjusted by moving the Z stage 770 in the vertical direction. The height position of the outer peripheral side surface 753 to be irradiated with the laser 722 is not particularly limited, but is preferably fixed in advance during measurement in order to improve measurement accuracy.

[0145] Next, while rotating the rotating table 710 once, the distance L between any point 753a of the outer peripheral side surface 753 and the displacement meter 720 is continuously measured. Here, "continuously measuring" means that the distance L is measured at least once during the period when the rotating table 710 rotates 1°. Considering the measurement accuracy and the efficiency of data processing, it is preferred to measure the distance L once during the period when the rotating table 710 rotates 0.05° to 0.5°, and it is more preferred to measure the distance L once during the period when the rotating table 710 rotates 0.1° to 0.3°. When the distance L between any point 753a of the outer peripheral side surface 753 in the normal direction of the point 753a is continuously measured and the displacement meter 720, if the distance between the rotation axis A of the rotating table 710 and the displacement meter is set to M, the distance (radius R) between the center of gravity position O of the measurement point in the cross section of the cylindrical honeycomb dried body 750 and the outer peripheral contour is represented by R=ML (refer to Figure 8). It should be noted that the distance L between any point 753a of the outer peripheral side surface 753 and the displacement meter 720 does not need to be the distance in the normal direction of any point 753a of the outer peripheral side surface 753. Even if it is a distance in other directions, the radius R can be geometrically calculated and can also be automatically calculated by the displacement meter. Therefore, through this measurement, the change in the radius R of the cylindrical honeycomb drying body 750 can be measured. The change in the radius R can be stored in the memory of the computer 740 in association with the rotation angle θ of the rotating table 710. In this way, the radius R can be associated with a specific part of the outer peripheral side surface.

[0146] In the process of continuously measuring the distance L between any location 753a of the outer peripheral side surface 753 of the cylindrical honeycomb dried body 750 and the displacement meter 720 using the displacement meter 720 while rotating the rotating table 710 once, it is preferred to set the circumferential speed of the outer peripheral side surface 753 in a manner that can improve the measurement accuracy and quickly perform the inspection. Although not limited, in one embodiment, the measurement process can be performed while rotating the cylindrical honeycomb dried body 750 at an average circumferential speed of 200 to 1200 mm / second. In view of the rapidity of the measurement, the lower limit of the average circumferential speed is preferably 235 mm / second or more. In addition, from the viewpoint of improving the measurement accuracy, the upper limit of the average circumferential speed is preferably 1000 mm / second or less.

[0147] Through the above steps, when a cross section of the cylindrical honeycomb dried body 750 perpendicular to the extending direction of the cells is observed from the front side in the direction of the extrusion molding in step A, the change in the radius R of the cylindrical honeycomb dried body 750 in the cross section can be correlated with the rotation angle θ of the rotating table 710. Therefore, D 1AVE , D 2AVE , D 3AVE , D 4AVE , D 5AVE , D 6AVE , D 7AVE , D 8AVE and droop (E AVE1 、E AVE2 、E AVE3 and E AVE4 ). These values ​​may also be automatically calculated by computer 740. AVE1 、E AVE2 、E AVE3 and E AVE4 They are defined as follows.

[0148] E AVE1 =(D 1AVE +D 4AVE +D 6AVE )-(D2AVE +D 5AVE +D 8AVE )

[0149] E AVE2 =(D 3AVE +D 6AVE +D 8AVE )-(D 2AVE +D 4AVE +D 7AVE )

[0150] E AVE3 =(D 2AVE +D 5AVE +D 8AVE )-(D 1AVE +D 4AVE +D 6AVE )

[0151] E AVE4 =(D 2AVE +D 4AVE +D 7AVE )-(D 3AVE +D 6AVE +D 8AVE )

[0152] In the above formula, the portion of the outer peripheral side surface located at the vertex during extrusion molding in step A is set to 0 rad, and the clockwise direction is set to the positive direction.

[0153] The average value of the distance (radius R) between the center position O of the cross section and the outer contour with a center angle (rad) ranging from -1 / 8π to +1 / 8π is defined as D 1AVE ,

[0154] The average value of the distance (radius R) between the center position O of the cross section and the outer contour with a center angle (rad) ranging from +1 / 8π to +3 / 8π is defined as D 2AVE ,

[0155] The average value of the distance (radius R) between the center position O of the cross section and the outer contour with a center angle (rad) ranging from +3 / 8π to +5 / 8π is defined as D 3AVE ,

[0156] The average value of the distance (radius R) between the center position O of the cross section and the outer contour with a center angle (rad) ranging from +5 / 8π to +7 / 8π is defined as D 4AVE ,

[0157] The average value of the distance (radius R) between the center position O of the cross section with a center angle (rad) ranging from +7 / 8π to +9 / 8π and the outer contour is defined as D 5AVE ,

[0158] The average value of the distance (radius R) between the center position O of the cross section and the outer contour with a center angle (rad) ranging from +9 / 8π to +11 / 8π is defined as D 6AVE ,

[0159] The average value of the distance (radius R) between the center position O of the cross section and the outer contour with a center angle (rad) ranging from +11 / 8π to +13 / 8π is defined as D 7AVE ,

[0160] The average value of the distance (radius R) between the center position O of the cross section and the outer contour with a center angle (rad) ranging from +13 / 8π to +15 / 8π is defined as D 8AVE (Refer to Fig. 9 ).

[0161] (Process D: Determine E AVE1 、E AVE2 、E AVE3 and E AVE4 The minimum value in

[0162] In step D, determine the sag amount E calculated in step C. AVE1 、E AVE2 、E AVE3 and E AVE4 This is because E AVE1 、E AVE2 、E AVE3 and E AVE4 The minimum sagging value is used as a reference to determine the direction of the cylindrical honeycomb dried body in the continuous firing furnace for firing. AVE1 、E AVE2 、E AVE3 and E AVE4 The smallest values ​​in are mostly negative. However, it is difficult to predict E AVE1 、E AVE2 、E AVE3 and E AVE4 Which one of them becomes the smallest value.

[0163] For example, in (D 1AVE +D 4AVE +D 6AVE )-(D 2AVE +D 5AVE +D 8AVE )=E AVE1 When it is the minimum value and a negative value, it means that the radius R from +1 / 8π to +3 / 8π, the radius R from +7 / 8π to +9 / 8π, and the radius R from +13 / 8π to +15 / 8π are relatively long and deviate from a perfect circle.

[0164] (Step E: Firing of Cylindrical Honeycomb Dried Body)

[0165] In step E, the cylindrical honeycomb dried body is placed on a shelf in a manner that the cell extension direction is parallel to the vertical direction and the portion of the predetermined outer peripheral side surface determined according to the minimum value is located at the front, and the cylindrical honeycomb dried body is fired while passing through a continuous firing furnace to obtain a cylindrical honeycomb fired body. It does not matter which bottom surface of the cylindrical honeycomb dried body is set as the top. The firing step also depends on the material composition of the cylindrical honeycomb dried body, and can be performed, for example, by heating the pre-fired body to 1400-1450° C. in an air atmosphere and maintaining it for 3-10 hours.

[0166] When a cylindrical honeycomb dried body is placed on a shelf in such a manner that the cell extension direction is parallel to the vertical direction and is fired while passing through a continuous firing furnace, it is known from experience that radial firing shrinkage tends to be relatively large near the outer peripheral side surface located at 45° right, 45° left, and 180° rear relative to the traveling direction. Fig.10 Schematically shown in FIG. The present invention is not intended to be limited by theory, but it is believed that this is caused by the wind direction in the firing furnace and the temperature distribution difference within the individual. By implementing step D, the portion of the outer peripheral side surface where the radial length of the cylindrical honeycomb dried body is relatively large is grasped based on the minimum value of the droop amount. Therefore, in the firing step, by combining the above-mentioned empirical rules and firing the cylindrical honeycomb dried body in a direction close to a perfect circle, the deformation during drying can be corrected.

[0167] Specifically, when the above minimum value is E AVE1 When the minimum value is E, the part of the outer peripheral side corresponding to 0rad is located at the front. AVE2 When the minimum value is E, the part of the outer peripheral side corresponding to 4 / 8πrad is located at the front. AVE3 When the minimum value is E, the part of the outer peripheral side corresponding to 8 / 8πrad is located at the front. AVE4 When the cylindrical honeycomb dried body is placed on the shelf, the portion of the outer peripheral side surface corresponding to 12 / 8πrad is located at the front.

[0168] For example, as mentioned above, in the above minimum value E AVE1When, the radius R from +1 / 8π to +3 / 8π, the radius R from +7 / 8π to +9 / 8π, and the radius R from +13 / 8π to +15 / 8π are relatively long and deviate from the perfect circle. Therefore, if the cylindrical honeycomb dried body is placed on the shelf in a manner such that the portion of the peripheral side corresponding to 0rad is located at the front, the radial firing shrinkage is relatively large near the peripheral side located near 45° right (near +2 / 8π), near 45° left (near +14 / 8π), and near 180° rear (near +8 / 8π) relative to the traveling direction. According to experience, if the cylindrical honeycomb dried body is fired irregularly, the roundness of the fired body is deteriorated by about 0.2 mm on average compared with the dried body, but by causing the portion of the peripheral side corresponding to it to shrink significantly compared with other peripheral sides during firing, the deterioration of the roundness can be suppressed, and preferably the roundness can also be improved.

[0169] However, even if the deformation of the cylindrical honeycomb dried body can be corrected during firing, there is a limit to the correction range. Therefore, it is also possible to determine whether the minimum value determined in step D satisfies a predetermined benchmark, and to implement step E only when the minimum value satisfies the benchmark. According to the research of the present inventors, if a cylindrical honeycomb dried body is placed on a shelf using the above-mentioned loading method and fired in a continuous firing furnace, the minimum value increases by about 0.2 mm regardless of the diameter and material of the cylindrical honeycomb dried body. Therefore, from the viewpoint of making the cross-section of the cylindrical honeycomb fired body close to a perfect circle, the predetermined benchmark is preferably that the minimum value is in the range of -0.3 mm to -0.1 mm.

[0170] In addition, it is preferable that it is determined whether the minimum value determined in step D satisfies a predetermined criterion. If the minimum value does not satisfy the predetermined criterion, step E is not performed but step F of manufacturing an annular mask is performed, wherein the inner circumference contour of the annular mask is changed according to the minimum value so that the inner circumference contour of the cylindrical honeycomb dried body to be manufactured next time is equal to or smaller than that of the cylindrical honeycomb dried body. AVE1 、E AVE2 、E AVE3 and E AVE4 The minimum value in satisfies the predetermined benchmark, and then, steps A to D are repeated again using the changed annular mask.

[0171] For example, in a cylindrical honeycomb drying body, the minimum value is E AVE1 = -0.4mm, and the predetermined standard is "the minimum value is in the range of -0.3mm to -0.1mm", it is possible to make E AVE1 The ring mask is corrected in a manner close to -0.2 mm. More specifically, due to E AVE1 =(D 1AVE +D 4AVE+D 6AVE )-(D 2AVE +D 5AVE +D 8AVE ), so consider using 2AVE , D 5AVE and D 8AVE The diameter of the corresponding portion of the annular mask becomes relatively smaller (the inner peripheral contour is reduced).

[0172] In the present embodiment, the droop amount is calculated based on the “average value” of the distance between the center of gravity position O and the outer peripheral contour in a predetermined plurality of angle ranges for the cross section of the cylindrical honeycomb dried body, but the droop amount can be defined not only by the “average value” but also by the “maximum value” or “minimum value”.

[0173] Therefore, in another embodiment of the present invention, in step C, calculate:

[0174] (D 1MAX +D 4MAX +D 6MAX )-(D 2MAX +D 5MAX +D 8MAX )=E MAX1

[0175] (D 3MAX +D 6MAX +D 8MAX )-(D 2MAX +D 4MAX +D 7MAX )=E MAX2

[0176] (D 2MAX +D 5MAX +D 8MAX )-(D 1MAX +D 4MAX +D 6MAX )=E MAX3 ,as well as

[0177] (D 2MAX +D 4MAX +D 7MAX )-(D 3MAX +D 6MAX +D 8MAX )=E MAX4 .

[0178] In the above formula, the portion of the outer peripheral side surface located at the vertex during extrusion molding in step A is set to 0 rad, and the clockwise direction is set to the positive direction.

[0179] The maximum value of the distance between the center of gravity position O of the cross section and the outer contour at the center angle (rad) from -1 / 8π to +1 / 8π is set to D1MAX ,

[0180] The maximum value of the distance between the center of gravity position O of the cross section and the outer contour when the center angle (rad) ranges from +1 / 8π to +3 / 8π is set to D 2MAX ,

[0181] The maximum value of the distance between the center of gravity position O of the cross section and the outer contour when the center angle (rad) is from +3 / 8π to +5 / 8π is set to D 3MAX ,

[0182] The maximum value of the distance between the center of gravity position O of the cross section and the outer contour when the center angle (rad) is from +5 / 8π to +7 / 8π is set to D 4MAX ,

[0183] The maximum value of the distance between the center of gravity position O of the cross section and the outer contour when the center angle (rad) is from +7 / 8π to +9 / 8π is set to D 5MAX ,

[0184] The maximum value of the distance between the center of gravity position O of the cross section and the outer contour when the center angle (rad) is from +9 / 8π to +11 / 8π is set to D 6MAX ,

[0185] The maximum value of the distance between the center of gravity position O of the cross section and the outer contour when the center angle (rad) is from +11 / 8π to +13 / 8π is set to D 7MAX ,

[0186] The maximum value of the distance between the center of gravity position O of the cross section and the outer contour when the center angle (rad) is from +13 / 8π to +15 / 8π is set to D 8MAX .

[0187] E MAX1 、E MAX2 、E MAX3 and E MAX4 With E AVE1 、E AVE2 、E AVE3 and E AVE4 Similarly, calculation can be performed based on the measurement result using the displacement meter.

[0188] In another embodiment of the present invention, in step D, the E calculated in step C is determined. MAX1 、E MAX2 、E MAX3 and E MAX4 The minimum value in .

[0189] In another embodiment of the present invention, in step E, the extending direction of the cells is parallel to the vertical direction, and at the minimum value E MAX1When the minimum value is E, the part of the outer peripheral side corresponding to 0rad is located at the front. MAX2 When the minimum value is E, the part of the outer peripheral side corresponding to 4 / 8πrad is located at the front. MAX3 When the minimum value is E, the part of the outer peripheral side corresponding to 8 / 8πrad is located at the front. MAX4 When the cylindrical honeycomb dried body is placed on a shelf in such a manner that the portion of the outer peripheral side surface corresponding to 12 / 8πrad is located at the front, the cylindrical honeycomb dried body is fired while passing through a continuous firing furnace to obtain a cylindrical honeycomb fired body.

[0190] In another embodiment of the present invention, it is determined that E determined in step D MAX1 、E MAX2 、E MAX3 and E MAX4 The minimum value in satisfies a predetermined criterion, and step E is performed only when the minimum value satisfies the criterion.

[0191] In another embodiment of the present invention, it is determined that E determined in step D MAX1 、E MAX2 、E MAX3 and E MAX4 The above minimum value in satisfies a predetermined criterion. When the above minimum value does not satisfy the predetermined criterion, step E is not performed and step F of making an annular mask is performed. The annular mask changes the inner circumference profile according to the minimum value so that the E of the cylindrical honeycomb dried body to be made next time is MAX1 、E MAX2 、E MAX3 and E MAX4 The minimum value in satisfies the above-mentioned predetermined criterion, and then, steps A to D are repeated again using the changed annular mask.

[0192] In another embodiment of the present invention, the predetermined reference can be set to E MAX1 、E MAX2 、E MAX3 and E MAX4 The above minimum value is in the range of -0.3mm to -0.1mm.

[0193] In another embodiment of the present invention, in step C, calculate:

[0194] (D 1MIN +D 4MIN +D 6MIN )-(D 2MIN +D 5MIN +D 8MIN)=E MIN1

[0195] (D 3MIN +D 6MIN +D 8MIN )-(D 2MIN +D 4MIN +D 7MIN )=E MIN2

[0196] (D 2MIN +D 5MIN +D 8MIN )-(D 1MIN +D 4MIN +D 6MIN )=E MIN3 ,as well as

[0197] (D 2MIN +D 4MIN +D 7MIN )-(D 3MIN +D 6MIN +D 8MIN )=E MIN4 .

[0198] In the above formula, the portion of the outer peripheral side surface located at the vertex during extrusion molding in step A is set to 0 rad, and the clockwise direction is set to the positive direction.

[0199] The minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from -1 / 8π to +1 / 8π is set to D 1MIN ,

[0200] The minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +1 / 8π to +3 / 8π is set to D 2MIN ,

[0201] The minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +3 / 8π to +5 / 8π is set to D 3MIN ,

[0202] The minimum value of the distance between the center of gravity position O of the cross section and the outer contour when the center angle (rad) is from +5 / 8π to +7 / 8π is set to D 4MIN ,

[0203] The minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +7 / 8π to +9 / 8π is set to D 5MIN ,

[0204] The minimum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle (rad) from +9 / 8π to +11 / 8π is set to D6MIN ,

[0205] The minimum value of the distance between the center of gravity position O of the cross section and the outer contour when the center angle (rad) is from +11 / 8π to +13 / 8π is set to D 7MIN ,

[0206] The minimum value of the distance between the center of gravity position O of the cross section and the outer contour when the center angle (rad) is from +13 / 8π to +15 / 8π is set to D 8MIN .

[0207] E MIN1 、E MIN2 、E MIN3 and E MIN4 With E AVE1 、E AVE2 、E AVE3 and E AVE4 Similarly, calculation can be performed based on the measurement result using the displacement meter.

[0208] In addition, in another embodiment of the present invention, regarding E MIN1 、E MIN2 、E MIN3 and E MIN4 , determine the E determined in step D MIN1 、E MIN2 、E MIN3 and E MIN4 The process E is performed only when the minimum value satisfies a predetermined criterion.

[0209] In another embodiment of the present invention, it is determined that E determined in step D MIN1 、E MIN2 、E MIN3 and E MIN4 The above minimum value in satisfies a predetermined criterion. When the above minimum value does not satisfy the predetermined criterion, step E is not performed and step F of making an annular mask is performed. The annular mask changes the inner circumference profile according to the minimum value so that the E of the cylindrical honeycomb dried body to be made next time is MIN1 、E MIN2 、E MIN3 and E MIN4 The minimum value in satisfies the above-mentioned predetermined criterion, and then, steps A to D are repeated again using the changed annular mask.

[0210] In another embodiment of the present invention, the predetermined reference may be set to E MIN1 、E MIN2 、E MIN3 and E MIN4The minimum value is in the range of -0.3mm to -0.1mm.

[0211] A degreasing process may also be performed before firing. The combustion temperature of the binder is about 200°C, and the combustion temperature of the pore-forming material is about 300-1000°C. Therefore, the degreasing process can be performed by heating the honeycomb formed body to a range of about 200-1000°C. The heating time is not particularly limited, but is usually about 10-100 hours. The cylindrical honeycomb dried body after the degreasing process is called a pre-fired body.

[0212] [Example]

[0213] The following examples and comparative examples relate to a method for producing a cylindrical honeycomb fired body having the following design specifications.

[0214] Overall shape: cylindrical, diameter 158mm x height 100mm

[0215] Cell shape in a cross section perpendicular to the cell flow direction: square

[0216] Cell density (number of cells per unit cross-sectional area): 600 cells / square inch

[0217] Wall thickness: 69μm

[0218] Porosity: 27%

[0219] <Test Examples 1 to 9>

[0220] (1. Production of cylindrical honeycomb sintered body)

[0221] In 100 parts by mass of cordierite raw materials, 1 part by mass of pore-forming material, 30 parts by mass of dispersion medium, 8 parts by mass of organic binder, and 1 part by mass of dispersant are added, mixed, kneaded, and molded clay is prepared. As cordierite raw materials, alumina, aluminum hydroxide, kaolin, talc, and silicon dioxide are used. Water is used as a dispersion medium, a water-absorbent resin is used as a pore-forming material, hydroxypropyl methylcellulose is used as an organic binder, and ethylene glycol is used as a dispersant.

[0222] The clay is put into an extrusion molding device, and extrusion molding is performed through a die and an annular mask to obtain a cylindrical honeycomb molded body, wherein the die defines the opening shape of the predetermined pores, and the annular mask is arranged downstream of the die and has an inner peripheral contour (a perfect circle with a diameter of 175.0 mm) for defining the outer peripheral contours of the first bottom surface and the second bottom surface. The direction of extrusion molding is set to the horizontal direction. After dielectric drying and hot air drying are performed on the cylindrical honeycomb molded bodies involved in each test example, the two bottom surfaces are cut in a manner to become a predetermined size to obtain a cylindrical honeycomb dried body. During dielectric drying and hot air drying, the body is arranged in the dryer in a direction in which the extension direction of the pores becomes a vertical direction, and is dried while passing through the dryer in a manner in which the portion of the outer peripheral side surface located at the vertex during extrusion molding is located at the front.

[0223] exist Figure 7 On the rotating table 710 of the shape measuring device 700 shown in FIG. 1 , a cylindrical honeycomb dried body is placed in such a manner that the rotation axis A coincides with the center of gravity position O of the bottom surface on the upper side of the cylindrical honeycomb dried body 750, and through the aforementioned steps, while the rotating table 710 is rotated once (average peripheral speed of 553 mm / sec), the distance between any point 753a on the outer peripheral side surface 753 and the displacement meter 720 in the normal direction is continuously measured (measured once every 0.12° rotation of the rotating table). Based on the measurement results, D is calculated when a cross section perpendicular to the extending direction of the cells of the cylindrical honeycomb dried body is observed from the front side in the advancing direction of the extrusion molding in step A. 1AVE , D 2AVE , D 3AVE , D 4AVE , D 5AVE , D 6AVE , D 7AVE , D 8AVE , and then calculate the sag amount (E AVE1 、E AVE2 、E AVE3 and E AVE4 ). As the displacement meter 720, a laser displacement meter of model ILD2300-100 manufactured by Micro-Epsilon Corporation was used. The height position of the outer peripheral side surface 753 irradiated with the laser 722 was set to the center of the cylindrical honeycomb dried body. In addition, the aforementioned roundness was obtained from the measurement results. The results are shown in Table 1. Although the manufacturing conditions of the cylindrical honeycomb formed body and the cylindrical honeycomb dried body involved in each test example were not intentionally changed, as shown in Table 1, some dimensional changes occurred.

[0224] Confirmed E AVE1 、E AVE2 、E AVE3 and E AVE4The results are shown in Table 1: the minimum value of these four parameters and the parameter showing the minimum value.

[0225] Next, regarding Test Examples 1 to 6 and 9, the extending direction of the cells was parallel to the vertical direction and the minimum value was E. AVE1 When the minimum value is E, the part of the outer peripheral side corresponding to 0rad is located at the front. AVE2 When the minimum value is E, the part of the outer peripheral side corresponding to 4 / 8πrad is located at the front. AVE3 When the minimum value is E, the part of the outer peripheral side corresponding to 8 / 8πrad is located at the front. AVE4 When the cylindrical honeycomb dried body is placed on the shelf, the portion of the outer peripheral side surface corresponding to 12 / 8πrad is located at the front.

[0226] In Test Example 7, the cylindrical honeycomb dried body was placed on the shelf so that the extending direction of the cells was parallel to the vertical direction and the portion of the outer peripheral side surface corresponding to 0 rad was located at the front.

[0227] In Test Example 8, the cylindrical honeycomb dried body was placed on the shelf so that the extending direction of the cells was parallel to the vertical direction and the portion of the outer peripheral side surface corresponding to 8 / 8πrad was located at the front.

[0228] Thereafter, the shelf having the cylindrical honeycomb dried body placed thereon was placed on a carriage and passed through a degreasing zone and a firing zone in a continuous firing furnace, whereby firing was performed under the following conditions to obtain a cylindrical honeycomb fired body.

[0229] [Firing conditions]

[0230] Maintaining temperature of firing area: 1430℃

[0231] Holding time at temperature: 240 minutes

[0232] The flow direction of the gas in the furnace: In the temperature rising area and the first half of the temperature holding area that have the greatest impact on the sintering shrinkage, the air is relatively facing the workpiece.

[0233] Burner location: upper side and lower side of the furnace

[0234] The cylindrical honeycomb fired bodies according to the obtained test examples were also measured using the shape measuring device 700 in the same manner as the cylindrical honeycomb dried body, and D 1AVE , D 2AVE , D 3AVE , D 4AVE , D 5AVE , D 6AVE , D 7AVE , D8AVE . Then, the droop amount after firing is calculated for the parameter showing the minimum value among the four droop amounts obtained for the dry body. The results are shown in Table 1. In addition, the roundness of the cylindrical honeycomb fired body is also calculated in the same way. As described above, if the cylindrical honeycomb dried body is fired irregularly, the roundness of the fired body deteriorates by about 0.2 mm on average compared to the dry body. Therefore, if the deterioration of the roundness is less than 0.2 mm, it is judged that a meaningful improvement is observed. Therefore, when the deterioration of the roundness is less than 0.2 mm, it is set to "OK", and when it is greater than 0.2 mm, it is set to "NG". The results are shown in Table 1.

[0235] [Table 1]

[0236]

[0237] <Inspection>

[0238] As for Test Examples 1 to 6 and 9, it can be seen that by optimizing the orientation of the cylindrical honeycomb dried body when firing the cylindrical honeycomb dried body, the deterioration of the roundness of the obtained cylindrical honeycomb fired body during firing is suppressed compared with Test Examples 7 and 8. In addition, the change in the droop amount before and after firing of the parameter showing the minimum value among the four droop amounts obtained from the cylindrical honeycomb dried body is about +0.2 mm, so based on this, the acceptance standard of the minimum value in the cylindrical honeycomb dried body is determined, thereby judging whether it is possible to enter the firing process or whether the inner peripheral profile of the annular mask should be changed to produce a molded body again.

Claims

1. A method for manufacturing a cylindrical honeycomb fired body, wherein the cylindrical honeycomb fired body has an outer peripheral side surface and partition walls, wherein the partition walls are arranged on the inner peripheral side of the outer peripheral side surface and divide a plurality of cells forming a flow path from a first bottom surface to a second bottom surface, The manufacturing method comprises: Step A, extruding a clay body containing a ceramic raw material, a pore-forming material, a binder and a dispersion medium through a die and an annular mask in an orientation in which the extending direction of the cells is horizontal, and cutting it into a predetermined length, thereby manufacturing a cylindrical honeycomb formed body having a front side in the advancing direction of the extrusion molding as a first bottom surface and a rear side as a second bottom surface, wherein the die defines the opening shape of the plurality of cells, and the annular mask is provided downstream of the die and has an inner peripheral contour for defining the outer peripheral contours of the first bottom surface and the second bottom surface; Step B, drying the cylindrical honeycomb formed body to obtain a cylindrical honeycomb dried body; In step C, assuming that a cross section perpendicular to the extending direction of the cells of the cylindrical honeycomb dried body is observed from the front side of the advancing direction of the extrusion molding in step A, the portion of the outer peripheral side surface located at the vertex during the extrusion molding in step A is set to 0rad, the clockwise direction is set to the positive direction, and the average value of the distance between the center position O of the cross section with a central angle of -1 / 8π to +1 / 8π and the outer peripheral contour is set to D 1AVE , the average value of the distance between the center of gravity position O of the cross section with a center angle of +1 / 8π to +3 / 8π and the outer contour is set as D 2AVE , the average value of the distance between the center of gravity position O of the cross section with a center angle of +3 / 8π to +5 / 8π and the outer contour is set as D 3AVE , the average value of the distance between the center of gravity position O of the cross section with a center angle of +5 / 8π to +7 / 8π and the outer contour is set as D 4AVE , the average value of the distance between the center of gravity position O of the cross section with a center angle of +7 / 8π to +9 / 8π and the outer contour is set as D 5AVE , the average value of the distance between the center of gravity position O of the cross section with a center angle of +9 / 8π to +11 / 8π and the outer contour is set as D 6AVE , the average value of the distance between the center position O of the cross section with a center angle of +11 / 8π to +13 / 8π and the outer contour is set as D 7AVE , the average value of the distance between the center of gravity position O of the cross section with a center angle of +13 / 8π to +15 / 8π and the outer contour is set as D 8AVE , calculate: (D 1AVE +D 4AVE +D 6AVE )-(D 2AVE +D 5AVE +D 8AVE )=E AVE1 (D 3AVE +D 6AVE +D 8AVE )-(D 2AVE +D 4AVE +D 7AVE )=E AVE2 (D 2AVE +D 5AVE +D 8AVE )-(D 1AVE +D 4AVE +D 6AVE )=E AVE3 ,as well as (D 2AVE +D 4AVE +D 7AVE )-(D 3AVE +D 6AVE +D 8AVE )=E AVE4 , The unit of the central angle is rad; Step D, determine E calculated in step C AVE1 、E AVE2 、E AVE3 and E AVE4 The minimum value in ; as well as Step E, in which the extending direction of the cells is parallel to the vertical direction and the minimum value is E AVE1 When the minimum value is E, the part of the outer peripheral side corresponding to 0rad is located at the front. AVE2 When the minimum value is E, the part of the outer peripheral side corresponding to 4 / 8πrad is located at the front. AVE3 When the minimum value is E, the part of the outer peripheral side corresponding to 8 / 8πrad is located at the front. AVE4 When the cylindrical honeycomb dried body is placed on a shelf in such a manner that the portion of the outer peripheral side surface corresponding to 12 / 8πrad is located at the front, the cylindrical honeycomb dried body is fired while passing through a continuous firing furnace to obtain a cylindrical honeycomb fired body.

2. The manufacturing method according to claim 1, comprising: In step B, the cells are arranged in a dryer in a vertical direction, and dried while passing through the dryer such that the portion of the outer peripheral side surface located at the apex during extrusion molding in step A is located first.

3. The manufacturing method according to claim 1, wherein: It is determined whether the minimum value determined in step D satisfies a predetermined criterion, and step E is performed only when the minimum value satisfies the criterion.

4. The manufacturing method according to claim 3, comprising: It is determined whether the minimum value determined in step D satisfies a predetermined criterion. If the minimum value does not satisfy the predetermined criterion, step E is not performed but step F of manufacturing an annular mask is performed. The annular mask changes the inner circumference profile according to the minimum value so that the inner circumference of the cylindrical honeycomb dried body to be manufactured next time is equal to or smaller than step E. AVE1 、E AVE2 、E AVE3 and E AVE4 The minimum value in satisfies the predetermined benchmark, and then, steps A to D are repeated again using the changed annular mask.

5. The manufacturing method according to claim 3 or 4, wherein: The predetermined reference is that the minimum value is in the range of -0.3 mm to -0.1 mm.

6. The manufacturing method according to claim 1 or 2, comprising: In process C, in order to calculate E AVE1 、E AVE2 、E AVE3 and E AVE4 , and carry out the following steps in sequence: The step of placing the cylindrical honeycomb dried body on a rotating table with the first bottom surface or the second bottom surface facing upward; and A step of continuously measuring the distance between any one point on the outer peripheral side surface of the cylindrical honeycomb dried body and the displacement meter using a displacement meter while rotating the rotating table once.

7. A method for manufacturing a cylindrical honeycomb fired body, the cylindrical honeycomb fired body having an outer peripheral side surface and partition walls, the partition walls being arranged on the inner peripheral side of the outer peripheral side surface and dividing a plurality of cells forming a flow path from a first bottom surface to a second bottom surface, The manufacturing method comprises: Step A, extruding a clay containing a ceramic raw material, a pore-forming material, a binder and a dispersion medium through a die and an annular mask in an orientation in which the extending direction of the cells is horizontal, and cutting it into a predetermined length, thereby manufacturing a cylindrical honeycomb molded body having a front side in the traveling direction of the extrusion molding as a first bottom surface and a rear side as a second bottom surface, wherein the die defines the opening shape of the plurality of cells, and the annular mask is provided downstream of the die and has an inner peripheral contour for defining the outer peripheral contours of the first bottom surface and the second bottom surface; Step B, drying the cylindrical honeycomb formed body to obtain a cylindrical honeycomb dried body; In step C, assuming that a cross section perpendicular to the extending direction of the cells of the cylindrical honeycomb dried body is observed from the front side of the advancing direction of the extrusion molding in step A, the portion of the outer peripheral side surface located at the vertex during the extrusion molding in step A is set to 0rad, the clockwise direction is set to the positive direction, and the maximum value of the distance between the center position O of the cross section with a central angle ranging from -1 / 8π to +1 / 8π and the outer peripheral contour is set to D 1MAX , the maximum value of the distance between the center of gravity position O of the cross section and the outer contour with a center angle from +1 / 8π to +3 / 8π is set to D 2MAX , the maximum value of the distance between the center of gravity position O of the cross section with a center angle from +3 / 8π to +5 / 8π and the outer contour is set as D 3MAX , the maximum value of the distance between the center of gravity position O of the cross section and the outer contour at the center angle from +5 / 8π to +7 / 8π is set to D 4MAX , the maximum value of the distance between the center of gravity position O of the cross section with a center angle from +7 / 8π to +9 / 8π and the outer contour is set as D 5MAX , the maximum value of the distance between the center of gravity position O of the cross section with a center angle from +9 / 8π to +11 / 8π and the outer contour is set as D 6MAX , the maximum value of the distance between the center of gravity position O of the cross section with a center angle from +11 / 8π to +13 / 8π and the outer contour is set as D 7MAX , the maximum value of the distance between the center of gravity position O of the cross section and the outer contour at the center angle from +13 / 8π to +15 / 8π is set to D 8MAX , calculate: (D 1MAX +D 4MAX +D 6MAX )-(D 2MAX +D 5MAX +D 8MAX )=E MAX1 (D 3MAX +D 6MAX +D 8MAX )-(D 2MAX +D 4MAX +D 7MAX )=E MAX2 (D 2MAX +D 5MAX +D 8MAX )-(D 1MAX +D 4MAX +D 6MAX )=E MAX3 ,as well as (D 2MAX +D 4MAX +D 7MAX )-(D 3MAX +D 6MAX +D 8MAX )=E MAX4 , The unit of the central angle is rad; Step D, determine E calculated in step C MAX1 、E MAX2 、E MAX3 and E MAX4 The minimum value in ; as well as Step E, in which the extending direction of the cells is parallel to the vertical direction and the minimum value is E MAX1 When the minimum value is E, the part of the outer peripheral side corresponding to 0rad is located at the front. MAX2 When the minimum value is E, the part of the outer peripheral side corresponding to 4 / 8πrad is located at the front. MAX3 When the minimum value is E, the part of the outer peripheral side corresponding to 8 / 8πrad is located at the front. MAX4 When the cylindrical honeycomb dried body is placed on a shelf in such a manner that the portion of the outer peripheral side surface corresponding to 12 / 8πrad is located at the front, the cylindrical honeycomb dried body is fired while passing through a continuous firing furnace to obtain a cylindrical honeycomb fired body.

8. The manufacturing method according to claim 7, comprising: In step B, the cells are arranged in a dryer in a vertical direction, and dried while passing through the dryer such that the portion of the outer peripheral side surface located at the apex during extrusion molding in step A is located first.

9. The manufacturing method according to claim 7, wherein: It is determined whether the minimum value determined in step D satisfies a predetermined criterion, and step E is performed only when the minimum value satisfies the criterion.

10. The manufacturing method according to claim 9, comprising: It is determined whether the minimum value determined in step D satisfies a predetermined criterion. If the minimum value does not satisfy the predetermined criterion, step E is not performed but step F of manufacturing an annular mask is performed. The annular mask changes the inner circumference profile according to the minimum value so that the inner circumference of the cylindrical honeycomb dried body to be manufactured next time is equal to or smaller than step E. MAX1 、E MAX2 、E MAX3 and E MAX4 The minimum value in satisfies the predetermined benchmark, and then steps A to D are repeated again using the changed annular mask.

11. The manufacturing method according to claim 9 or 10, wherein: The predetermined reference is that the minimum value is in the range of -0.3 mm to -0.1 mm.

12. The manufacturing method according to claim 7 or 8, comprising: In process C, in order to calculate E MAX1 、E MAX2 、E MAX3 and E MAX4 , and carry out the following steps in sequence: The step of placing the cylindrical honeycomb dried body on a rotating table with the first bottom surface or the second bottom surface facing upward; and A step of continuously measuring the distance between any one point on the outer peripheral side surface of the cylindrical honeycomb dried body and the displacement meter using a displacement meter while rotating the rotating table once.

13. A method for manufacturing a cylindrical honeycomb fired body, the cylindrical honeycomb fired body having an outer peripheral side surface and partition walls, the partition walls being arranged on the inner peripheral side of the outer peripheral side surface and dividing a plurality of cells forming a flow path from a first bottom surface to a second bottom surface, The manufacturing method comprises: Step A, extruding a clay containing a ceramic raw material, a pore-forming material, a binder and a dispersion medium through a die and an annular mask in an orientation in which the extending direction of the cells is horizontal, and cutting it into a predetermined length, thereby manufacturing a cylindrical honeycomb molded body having a front side in the traveling direction of the extrusion molding as a first bottom surface and a rear side as a second bottom surface, wherein the die defines the opening shape of the plurality of cells, and the annular mask is provided downstream of the die and has an inner peripheral contour for defining the outer peripheral contours of the first bottom surface and the second bottom surface; Step B, drying the cylindrical honeycomb formed body to obtain a cylindrical honeycomb dried body; In step C, assuming that a cross section perpendicular to the extending direction of the cells of the cylindrical honeycomb dried body is observed from the front side of the advancing direction of the extrusion molding in step A, the portion of the outer peripheral side surface located at the vertex during the extrusion molding in step A is set to 0rad, the clockwise direction is set to the positive direction, and the minimum value of the distance between the center position O of the cross section with a central angle ranging from -1 / 8π to +1 / 8π and the outer peripheral contour is set to D 1MIN , the minimum value of the distance between the center of gravity position O of the cross section with a center angle from +1 / 8π to +3 / 8π and the outer contour is set as D 2MIN , the minimum value of the distance between the center of gravity position O of the cross section with a center angle from +3 / 8π to +5 / 8π and the outer contour is set as D 3MIN , the minimum value of the distance between the center of gravity position O of the cross section with a center angle from +5 / 8π to +7 / 8π and the outer contour is set as D 4MIN , the minimum value of the distance between the center of gravity position O of the cross section with a center angle from +7 / 8π to +9 / 8π and the outer contour is set as D 5MIN , the minimum value of the distance between the center of gravity position O of the cross section with a center angle from +9 / 8π to +11 / 8π and the outer contour is set as D 6MIN , the minimum value of the distance between the center of gravity position O of the cross section with a center angle from +11 / 8π to +13 / 8π and the outer contour is set as D 7MIN , the minimum value of the distance between the center of gravity position O of the cross section with a center angle from +13 / 8π to +15 / 8π and the outer contour is set as D 8MIN , calculate: (D 1MIN +D 4MIN +D 6MIN )-(D 2MIN +D 5MIN +D 8MIN )=E MIN1 (D 3MIN +D 6MIN +D 8MIN )-(D 2MIN +D 4MIN +D 7MIN )=E MIN2 (D 2MIN +D 5MIN +D 8MIN )-(D 1MIN +D 4MIN +D 6MIN )=E MIN3 ,as well as (D 2MIN +D 4MIN +D 7MIN )-(D 3MIN +D 6MIN +D 8MIN )=E MIN4 , The unit of the central angle is rad; Step D, determine E calculated in step C MIN1 、E MIN2 、E MIN3 and E MIN4 The minimum value in ; and Step E, in which the extending direction of the cells is parallel to the vertical direction and the minimum value is E MIN1 When the minimum value is E, the part of the outer peripheral side corresponding to 0rad is located at the front. MIN2 When the minimum value is E, the part of the outer peripheral side corresponding to 4 / 8πrad is located at the front. MIN3 When the minimum value is E, the part of the outer peripheral side corresponding to 8 / 8πrad is located at the front. MIN4 When the cylindrical honeycomb dried body is placed on a shelf in such a manner that the portion of the outer peripheral side surface corresponding to 12 / 8πrad is located at the front, the cylindrical honeycomb dried body is fired while passing through a continuous firing furnace to obtain a cylindrical honeycomb fired body.

14. The manufacturing method according to claim 13, comprising: In step B, the cells are arranged in a dryer in a vertical direction, and dried while passing through the dryer such that the portion of the outer peripheral side surface located at the apex during extrusion molding in step A is located first.

15. The manufacturing method according to claim 13, wherein: It is determined whether the minimum value determined in step D satisfies a predetermined criterion, and step E is performed only when the minimum value satisfies the criterion.

16. The manufacturing method according to claim 15, comprising: It is determined whether the minimum value determined in step D satisfies a predetermined criterion. If the minimum value does not satisfy the predetermined criterion, step E is not performed but step F of manufacturing an annular mask is performed. The annular mask changes the inner circumference profile according to the minimum value so that the inner circumference of the cylindrical honeycomb dried body to be manufactured next time is equal to or smaller than step E. MIN1 、E MIN2 、E MIN3 and E MIN4 The minimum value in satisfies the predetermined benchmark, and then steps A to D are repeated again using the changed annular mask.

17. The manufacturing method according to claim 15 or 16, wherein: The predetermined reference is that the minimum value is in the range of -0.3 mm to -0.1 mm.

18. The manufacturing method according to claim 13 or 14, comprising: In process C, in order to calculate E MIN1 、E MIN2 、E MIN3 and E MIN4 , and carry out the following steps in sequence: The step of placing the cylindrical honeycomb dried body on a rotating table with the first bottom surface or the second bottom surface facing upward; and A step of continuously measuring the distance between any one point on the outer peripheral side surface of the cylindrical honeycomb dried body and the displacement meter using a displacement meter while rotating the rotating table once.

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